Research Methods Overview of Research Methods Methods of

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 Research Methods

Research Methods

Overview of Research Methods § Methods of investigation/ research § Aims and Hypothesis §

Overview of Research Methods § Methods of investigation/ research § Aims and Hypothesis § Sampling techniques § Experimental designs § Reliability & Validity § Qualitative and Quantitative Data § probability, and level of significance

Methods of Research § Experimental § Field § Laboratory § Non-experimental § Observational techniques

Methods of Research § Experimental § Field § Laboratory § Non-experimental § Observational techniques § Self-report/ questionnaires/interviews § Case study § Correlational analysis (not tested) § Content analysis (not tested)

Methods of Research § Research methods are the ways psychologists test their ideas and

Methods of Research § Research methods are the ways psychologists test their ideas and explanations § psychology is a science and all sciences are based on the findings of investigations. § Experiments basically involve “meddling with” or manipulating situations to find out how one factor (e. g. giving lots of praise) affects another factor, (how well students perform in a psychology test) § The idea in experiments is that researchers keep some things the same (control them) while changing other factors and then measuring the results.

Methods of Research § For example, does giving children vitamin pills improve their IQ?

Methods of Research § For example, does giving children vitamin pills improve their IQ? § If women look at magazine pictures of models does it lower their self esteem? § Does taking Prozac make people fell less depressed? § There a number of ways of conducting experiments each with their own strengths and weaknesses.

Experiments § Researcher manipulates the independent variable to measure the effect on the dependent

Experiments § Researcher manipulates the independent variable to measure the effect on the dependent variable. § A true experiment has three key features: § The researcher manipulates an independent variable (IV) in order to investigate whethere is a change in a second variable, known as the dependent variable (DV) § All other variables, which might influence the results, are either controlled, held constant or eliminated. Unwanted variables are called confounding variables § Participants (Ps) are allocated to the experimental conditions randomly

Advantages of the Experimental Method § May be able to establish a cause-and-effect relationship

Advantages of the Experimental Method § May be able to establish a cause-and-effect relationship between the IV and the DV § Allows researchers to force the pace of the research because they do not have to wait for natural events to reproduce the appropriate scenario § An experiment generates quantitative data (numerical measures of the DV) which can be analyzed to allow the researcher to state how likely the results are to have occurred by chance 7

Advantages of the Experimental Method § It is possible to generalize the findings to

Advantages of the Experimental Method § It is possible to generalize the findings to the rest of the population from which the sample of participants has been draw, provided that a representative sample of participants was selected for the original experiment

Disadvantages of the Experimental Method • Participants in many experimental investigations reflect an over-representation

Disadvantages of the Experimental Method • Participants in many experimental investigations reflect an over-representation of males and of specific cultures, and are often student volunteers • Participants usually know that they are taking part in a psychological experiment and may therefore may subconsciously change their behavior, also known as demand characteristic. This can affect the results of the study • It is not always possible to carry out an experiment because it would either be inappropriate or unethical to do so 9

Laboratory Experiments § These are conducted in a special environment where variables can be

Laboratory Experiments § These are conducted in a special environment where variables can be carefully controlled. § Participants are usually aware that they are taking part in an experiment although they may not know the true aims/goals of the study § Provides the highest level of control over variables and are widely used in psychology § The psychology laboratory may be the only place where some sophisticated technical equipment can be used and accurate measurements made 10

Laboratory Experiments § Just because a study has been carried out in a laboratory

Laboratory Experiments § Just because a study has been carried out in a laboratory does not mean that it is necessarily an experiment. § Observation studies may also take place in laboratories

§ § § Laboratory- Advantages and Disadvantages Advantages § Replicability of procedures § Sophisticated

§ § § Laboratory- Advantages and Disadvantages Advantages § Replicability of procedures § Sophisticated measuring and recording equipment § Control over variables Weaknesses § Loss of validity § Risk of demand characteristics - where participants form an interpretation of the experiment's purpose and subconsciously change their behavior to fit that interpretation. Ethical issues § Consent § Deception § Use of animals 12

Field Experiments § Field experiments are experimental investigations carried out in the natural environment

Field Experiments § Field experiments are experimental investigations carried out in the natural environment of those being studied § The field experiment is used in situations where it is considered particularly important for research to take account of the natural environment § As with the laboratory experiment there is still deliberate manipulation of variables by the researcher but it is less likely that the participants know they are in an experiment. 13

§ Field- Advantages and Disadvantages Advantages § Improved ecological validity § Reduction of demand

§ Field- Advantages and Disadvantages Advantages § Improved ecological validity § Reduction of demand characteristics § Weaknesses § Establishing controls § Generalizing to other situations § Cost § Use of technical equipment § Ethical Issues § Consent § Confidentiality § Use of animals 14

Non- Experimental § Non-experimental methods include the following: § Observational techniques – where you

Non- Experimental § Non-experimental methods include the following: § Observational techniques – where you watch people and record their behaviour and information about them. § Self-report – this is where people tell you about themselves, through an interview or by filling in some sort of questionnaire § Case study – where one person or a small group of people are studied very intensely and lots of information is gathered about them.

Non- Experimental § Correlational analysis – where two pieces of information are collected than

Non- Experimental § Correlational analysis – where two pieces of information are collected than analysed to see if there is a relationship between them. § Content analysis – the analysis of language, certain words or certain activities in a chosen media (books, TV, magazines, the internet).

Non- Experimental § In a natural experiment, the researcher makes use of naturally occurring

Non- Experimental § In a natural experiment, the researcher makes use of naturally occurring differences in the independent variable (IV) § The researcher does not directly control the IV. § The approach is therefore best described as a quasi-experiment or naturalistic although some purists might even regard it as nonexperimental, or observational study. 17

Natural Experiments § The independent variable is not being manipulated by the experimenter but

Natural Experiments § The independent variable is not being manipulated by the experimenter but is changing or occurring naturally in the environment. § It may be the introduction of TV to a remote community for example. In this situation, the experimenter measures the effects (the changes in behavior) known as the dependent variable as a result of the naturally changing independent variable (introduction of TV).

Natural- Advantages and Disadvantages § Advantages § Reduction of demand characteristics § Lack of

Natural- Advantages and Disadvantages § Advantages § Reduction of demand characteristics § Lack of direct intervention § Disadvantages § Loss of control § Likelihood of the desired behavior being displayed § Ethical issues § Consent § Protection of participants § Confidentiality 19

Example of a Natural Experiment: Violence levels before and after the Kennedy assassination in

Example of a Natural Experiment: Violence levels before and after the Kennedy assassination in 1963

Observational Techniques § In observation research, behavior is observed and recorded and there is

Observational Techniques § In observation research, behavior is observed and recorded and there is usually no deliberate manipulation of variables § Observational research can differ in several important ways, depending on: § the setting of the study, e. g. naturalistic or laboratory-based § the role of the researcher, e. g. participant (involved) or non-participant (not involved) § the amount of structure imposed, e. g. use of a coding system to record instances of a behavior 21

Observational Techniques § Observations made can be either structured or unstructured. § Structured observation

Observational Techniques § Observations made can be either structured or unstructured. § Structured observation involves the use of tables of pre-determined categories of behavior and systematic sampling. § Unstructured observations are when the observer records everything that happens. Observer may use a diary method to record events, feelings, or moods or perhaps a video recording.

§ Observation- Advantages and Advantages Disadvantages § § Value as a preliminary research tool

§ Observation- Advantages and Advantages Disadvantages § § Value as a preliminary research tool § High ecological validity Weaknesses § § Control § Replication § Observer bias § Can only measure overt behavior § Costs § Coding systems § Generalizability of the findings Ethical issues § Privacy § Confidentially and consent § Use of the findings 23

Self-report Techniques: Questionnaires § Self-report techniques enable participants to provide information knowingly about specific

Self-report Techniques: Questionnaires § Self-report techniques enable participants to provide information knowingly about specific things relating to themselves § A survey – the systematic gathering of data from large numbers of people – usually uses questionnaires § The questionnaire is one type of self-report/ survey technique § Can acquire lots of data quickly. § Provides insight into people’s views, opinions, attitudes, past experiences and specific scenarios 24

§ Types of question § Closed questions-Restrict respondent to a predetermined set of responses

§ Types of question § Closed questions-Restrict respondent to a predetermined set of responses § Generate quantitative data § Open ended questions- Allow respondents to answer however they want § Generate qualitative data § Good practice: § Ask for one piece of information at a time § Allow for ‘don’t know’ where appropriate § Keep questions to minimum necessary § Use short, clearly phrased, questions § Avoid emotionally charged questions

§ Questionnaires- Advantages and Disadvantages § Simplicity § Speed and cost § Less influence

§ Questionnaires- Advantages and Disadvantages § Simplicity § Speed and cost § Less influence of interpersonal variables § Weaknesses § Problem with question wording, e. g. leading questions § Poorly designed questionnaires § Response rates § Researches effects and biases § Ethical issues § Privacy § Consent § Risk of harm § Debriefing and support 26

Self-report Techniques: Interviews § An interview is a face-to-face encounter where one person asks

Self-report Techniques: Interviews § An interview is a face-to-face encounter where one person asks another person a series of pre- determined questions. § The interview may be: § Structured § Unstructured- (like informal chats) § Semi-structured § Structured interviews: predetermined questions and usually produce quantitative data § Unstructured interviews: less rigid with only one or two opening questions decided in advance § Semi-structured interviews: use a mix of prepared questions with additional questions as needed 27

§ Interviews- Advantages and Advantages Disadvantages § Flexibility § Tackling sensitive topics § Different

§ Interviews- Advantages and Advantages Disadvantages § Flexibility § Tackling sensitive topics § Different types of interview § Weaknesses § Interpreting data § Time and effort involved § Limitations of interviewees’ responses § Effects of interpersonal variables § Demand characteristics § Need for training § Cost § Ethical issues § Privacy/ confidentiality § Consent § protection from harm and debriefing) 28

Case Studies § Case study research typically involves the indepth study over time of

Case Studies § Case study research typically involves the indepth study over time of a ‘case’ which can be a single individual, small group, event or discrete process. § Case studies often involve the use of interviews with the individual and family, friends, medical professionals etc. § Ethical issues § Similar to those involved in interviews and observation research § Level of intrusion 29

Case Studies- Advantages and Disadvantages § Advantages § Rich and interesting data § Challenging

Case Studies- Advantages and Disadvantages § Advantages § Rich and interesting data § Challenging existing theory § High validity § Efficient method as it only takes one case study to disprove a theory § Weaknesses § Low reliability of much case study research § Findings may be subjective § Selecting from large amounts of data § Distortions § Cannot generalize due to small samples

Content Analysis § Content analysis is a research tool used to indirectly observe the

Content Analysis § Content analysis is a research tool used to indirectly observe the presence of certain words, images or concepts within the media (e. g. advertisements, books, films etc. ). § For example, content analysis could be used to study sex-role stereotyping. Researchers quantify (i. e. count) and analyze (i. e. examine) the presence, meanings and relationships of words and concepts, then make inferences about the messages within the media, the writer(s), the audience, and even the culture and time of which these are a part.

Content Analysis- Advantages and Disadvantages § Advantages § detailed and easily analyzed material about

Content Analysis- Advantages and Disadvantages § Advantages § detailed and easily analyzed material about a particular aspect of society. § high in validity. § replication and verification of results should be possible. § Allows researchers to study people who may be difficult to access directly § Weaknesses § Observation bias § source of bias (material and content to be analyzed) § Misinterpretation may occur due to the people not actually being studied directly § Ethical issues § Few ethical issues as material is being studied, rather than people

Correlation § The term ‘correlation’ refers to a statistical technique that measures the relationship

Correlation § The term ‘correlation’ refers to a statistical technique that measures the relationship between two variables § For a correlational study, the data can be plotted as points on a scattergraph. A line of best fit is then drawn through the points to show the trend of the data. § A positive correlation: high values on one variable are associated with high values on another variable § A negative correlation: high values on one variable are associated with low values on another variable

Correlation § A correlation coefficient indicates the strength and direction of the association between

Correlation § A correlation coefficient indicates the strength and direction of the association between two variables: § The strength is indicated by the number (between 0 and 1) and the direction by the sign in front of the number § +1 is a perfect positive correlation § -1 is a perfect negative correlation

§ Correlation- Advantages and Disadvantages Advantages § Measuring the strength of relationships § Value

§ Correlation- Advantages and Disadvantages Advantages § Measuring the strength of relationships § Value to exploratory research § Can statistically analyze naturally occurring phenomena § Weaknesses § The issue of causality § Measurement of non-linear relationships § Ethical issues § Consent § Use of findings Example of a non-linear relationship 35

Experiments- Recap § An experiment is a study of cause and effect; it involves

Experiments- Recap § An experiment is a study of cause and effect; it involves the deliberate manipulation of one factor or variable, while trying to keep all other variables constant. § The researcher manipulates an independent variable (IV) in order to investigate whethere is a change in a second variable, known as the dependent variable (DV) § All other variables, which might influence the results, are either controlled, held constant or eliminated. Unwanted variables are called extraneous or confounding variables § Participants (Ps) are allocated to the experimental conditions randomly

Generating Research Aims/Goals § Starting point for any psychological research study is for the

Generating Research Aims/Goals § Starting point for any psychological research study is for the researcher to think carefully about what the investigation is trying to discover. § Then generate an appropriate aim -the purpose of the research/what they want to study and then makes the focus of the study explicit § In order to generate the research aim, the researcher needs to be clear about the purpose of the investigation § In some observational or survey research, the research aim may be fairly broad – for instance, describing what is happening rather than measuring something to test a prediction § In an experimental investigation, on the other hand, the aim may be to test a hypothesis 38

Formulating Hypotheses § An hypothesis is a clear, predictive and testable statement, made at

Formulating Hypotheses § An hypothesis is a clear, predictive and testable statement, made at the outset of an investigation, which indicates the expected outcome of a study § A hypothesis may be: § Directional – (one tailed) § Non-directional – (two tailed) § Null – States that there is no effect in a study 39

Hypothesis § A hypothesis is generated once psychologists have proposed a theory. § A

Hypothesis § A hypothesis is generated once psychologists have proposed a theory. § A directional hypothesis (one tailed) states that there will be a difference between two results and predicts what the difference will be. § A non-directional hypothesis (two tailed) states that there will be a difference between results, but does not state what the difference will be.

Hypothesis § The null hypothesis predicts that any significant difference between results is simply

Hypothesis § The null hypothesis predicts that any significant difference between results is simply down to chance. § This is tested using inferential statistics. § If results are found to not be statistically significant, then the researcher must reject the experimental hypothesis, and accept the null hypothesis.

Defining and Operationalizing Variables § A variable is something that may vary or change

Defining and Operationalizing Variables § A variable is something that may vary or change in some way and which can either be categorised or measured § Psychologists need to be able to define variables clearly if their research is to be scientifically credible and worthwhile § Operational definitions are descriptions of variables phrased in terms that are sufficiently precise to enable them to be identified and measured 1 42

Selection of Participants (Ps) § In order to conduct any experiment, Researchers first identify

Selection of Participants (Ps) § In order to conduct any experiment, Researchers first identify the target population (TP) - this is the whole group with which the study is concerned. § Next, researchers need people or animals to study. The participants (or subjects) which are to be used in the experiment are called a sample. § The sample should represent the population- the group of people from whom the sample is drawn. § Psychologists try not to use a biased sample -that is a sample that is not representative. § Ways to choose a sample from a target population: § Random § Opportunity § Volunteer § Stratified

Selecting Participants (Ps) and Sampling Techniques § Random sampling § Every person or item

Selecting Participants (Ps) and Sampling Techniques § Random sampling § Every person or item in a given target population has an equal chance of being selected for inclusion § Opportunity sampling § Also referred to as a ‘convenience sampling’ § Researcher selects anyone who is available to take part 44

Selecting Participants (Ps) and Sampling Techniques § Volunteer sampling § Ps select themselves, hence

Selecting Participants (Ps) and Sampling Techniques § Volunteer sampling § Ps select themselves, hence also referred to as ‘self-selected sampling’ § Stratified sampling § This sample is a proportional representation of the target population. The target population is broken down into smaller groups, for example gender or age. You then sample from those groups.

Random Sampling- Advantages and Disadvantages § Advantages § More representative § Avoids bias as

Random Sampling- Advantages and Disadvantages § Advantages § More representative § Avoids bias as the researcher does not have control over who is selected § Disadvantages § Chance of a 'freak' sample § Compared to other methods, it is timeconsuming as all the potential participants have to be identified before they can be selected

Opportunity Sampling- Advantages and Disadvantages § Advantages § Less time-consuming than other methods as

Opportunity Sampling- Advantages and Disadvantages § Advantages § Less time-consuming than other methods as participants are simply selected without the use of a system § Disadvantages § Sample likely to be biased as certain people will volunteer to be chosen § Researcher may show bias when selecting participants

Volunteer Sampling. Advantages and Disadvantages § Advantages § The participants would be very motivated

Volunteer Sampling. Advantages and Disadvantages § Advantages § The participants would be very motivated § It gives you access to a variety of people you normally would not have access to. § Disadvantages § not a representative sample since § Volunteers are most likely to all be similar, as volunteers tend to be more willing, and more eager to please than the wider population.

Stratified Sampling- Advantages and Disadvantages § Avoids the problems with 'freak' samples § Relatively

Stratified Sampling- Advantages and Disadvantages § Avoids the problems with 'freak' samples § Relatively objective § Disadvantages § More time-consuming than other techniques § May not be representative as all the key participant characteristics may not be identified for stratification

Ethical guidelines for research with human participants Consent form/Invitation letter Anonymity Physical or psychological

Ethical guidelines for research with human participants Consent form/Invitation letter Anonymity Physical or psychological risks are avoided Debriefing

Sample Activity Task: What type of sampling method has been used in each of

Sample Activity Task: What type of sampling method has been used in each of these examples? § A researcher wished to study memory in adults aged 18 -65 yrs. He stands in the high street of a town and stops people as they pass. § A university department undertook a study of mobile phone use in adolescents, using a questionnaire. The questionnaire was given to a group of students in a local comprehensive school, selected by placing all the students’ names in a container and drawing out 50 names. § A class of psychology students conducts a study on memory. They put a notice on the sixth form notice board asking for students who have an hour to spare.

Reliability § Reliability refers to the consistency of results § Scorer reliability or inter-rater

Reliability § Reliability refers to the consistency of results § Scorer reliability or inter-rater reliability – how closely different people who are marking a test or performance agree with each other § Test-retest reliability – if participants take the same test twice, would they get similar results § External reliability – consistency between measures. Measures are the same at different times and in different situations e. g a ruler. § Internal reliability – consistency within a method e. g measures the same construct throughout the research e. g a stop-watch.

Methods and Reliability § Experiment – high levels of control, so easy to replicate

Methods and Reliability § Experiment – high levels of control, so easy to replicate § Correlation – high – variables under investigation need to be quantified. This is done by using clear measures of behavior that are easy to use again. § Self-report – variable – Unstructured interviews are difficult to repeat. Questionnaires and structured interviews are easy to replicate as questions are set.

Methods and Reliability § Observation – variable – structured observations are more reliable as

Methods and Reliability § Observation – variable – structured observations are more reliable as they use coding systems, therefore other researchers can use them to conduct a similar observation. § Content analysis – variable – Quantitative content analyses are more reliable as they use numerical coding systems. Qualitative content analyses are subjective. § Case study – low – high levels of involvement and interpretation on the part of the researcher, so often subjective.

Validity § Validity refers to whether or not a test measures what it was

Validity § Validity refers to whether or not a test measures what it was designed to measure. § Internal validity - the extent to which study is free of design faults, which may affect results. § External validity - this means the extent to which generalization can be made from the test environment to other situations. § For example, case studies have low external validity, as they only study a small sample. § Ecological validity -a type of ‘external validity’. This means the extent to which generalization can be made from the test environment to other situations § Face validity – does the test LOOK like it is measuring what it is supposed to be measuring?

Decreasing Bias § Bias means distorted in some way so we don’t get a

Decreasing Bias § Bias means distorted in some way so we don’t get a clear reflection of the attitude or behavior being studied. § This occurs when either the researcher or the participants influence the results. § There are many types of bias such as experimenter bias, social desirability bias, observer bias, interviewer bias or sample bias. § Researchers can minimize bias by: § Disguise the purpose of the investigation: § Deception § Single and double blind

Relationship Between Researchers and Participants § Demand characteristics § Occur when participants try to

Relationship Between Researchers and Participants § Demand characteristics § Occur when participants try to make sense of the research situation that they find themselves in and act accordingly § e. g. Ps guess purpose of investigation and try to be ‘helpful’ or to present themselves favourably § Observer bias – observers know the goals of the research study or hypothesis and therefore allow this knowledge to influence their observations during the research. § Investigator effects § Result from the effects of a researcher’s behavior and characteristics on an investigation § e. g. investigator’s expectations; observer effects 57

Control of Extraneous Variables § They need to be controlled because they can obscure

Control of Extraneous Variables § They need to be controlled because they can obscure the effect of an independent variable on a dependent variable, or provide a false impression that an independent variable has produced changes when in fact it has not § Extraneous variables can result from: § Random errors (e. g. P’s level of motivation or state of mind) § Constant errors (e. g. failure to counterbalance; measuring errors) 58

Choosing an Experimental Design § The aim of successful experimental design is to: §

Choosing an Experimental Design § The aim of successful experimental design is to: § Determine the precise nature of the experimental task § Ensure that appropriate and precise measurements can be made § Enable all the data collected to be analyzed correctly § Eliminate all potential sources of ambiguity or bias § Ensure high levels of control over the independent and dependent variables § Often psychologists carry out a ‘dress rehearsal’ or pilot study, of their study before they go out into the world and conduct the research on a large number of people. § This enables the researcher to check for design faults. 1 59

Experimental Designs § There are 3 different experimental designs: § Independent § Repeated §

Experimental Designs § There are 3 different experimental designs: § Independent § Repeated § Matched § Independent groups § Different Ps used in each condition of the experiment § Design typically involves § A control and one or more experimental conditions § Ps are randomly allocated to conditions to try to ensure that participant variables do not differ systematically between conditions

Experimental Designs § Repeated measures § Each participant is exposed to each of the

Experimental Designs § Repeated measures § Each participant is exposed to each of the experimental conditions § The main disadvantage – risk of order effects – is addressed through counterbalancing or randomization § Matched Pairs § Each participant in one group/condition is carefully matched on all the variables considered to be relevant to the investigation with a participant in another group/condition

Independent Groups- Advantages and Disadvantages § Advantages § No order effects § Lower risk

Independent Groups- Advantages and Disadvantages § Advantages § No order effects § Lower risk of demand characteristics § Wide range of potential uses § Disadvantages § Participant variables may differ systematically between conditions § Requires twice as many Ps as a repeated measures design

Repeated Measures - Advantages and Disadvantages § Advantages § No individual differences between Ps

Repeated Measures - Advantages and Disadvantages § Advantages § No individual differences between Ps in different conditions § Fewer participants are needed § Disadvantages § Smaller range of potential uses compared to the independent design § Risk of order effects that may confound results (order effects can be reduced by randomizing the order of conditions

Matched Pairs- Advantages and Disadvantages § Advantages § Combines advantages of independent and repeated

Matched Pairs- Advantages and Disadvantages § Advantages § Combines advantages of independent and repeated measures designs § No order effects § Avoids some extraneous variables § Participant variables are reduced § Disadvantages § Matching pairs of Ps may be time-consuming and difficult § Large number of potential Ps needed to achieve matching § Expensive

 Quantitative and Qualitative Data § Numerical data is called quantitative data, it is

Quantitative and Qualitative Data § Numerical data is called quantitative data, it is easy to compare and analyze and find patterns. § Data that can’t be reduced to numbers and has lots of detail is called qualitative data. § Qualitative description § A psychologist uses qualitative description for two reasons: § To write about qualitative observations made during the experiment, incidental perhaps – how people responded to types of questions etc. § Sometimes data is qualitative – an interview, for example, that draws out possible reasons why a phenomenon may occur.

Quantitative and Qualitative Data § Quantitative usually displayed as: § Tables § Graphs §

Quantitative and Qualitative Data § Quantitative usually displayed as: § Tables § Graphs § Bar Chart § Histogram § Line Graph § Scattergram § Qualitative usually displayed as: § Data from naturalistic observational studies § Data from questionnaires § Data from interviews § Processes involved in content analysis

Probability and level of significance § Decimal value is preferred. § Statistics allow us

Probability and level of significance § Decimal value is preferred. § Statistics allow us to: § Decide whether measured differences are meaningful or due to chance § Decide whether relationships are real § Decide whether one variable predicts another

Level of significance § example= P < 0. 05 § 5/100 times, the results

Level of significance § example= P < 0. 05 § 5/100 times, the results are down to chance. § 95% of the time, the change is down to the IV. § 'P' stands for the probability that chance factors are responsible for the results. § 1% significance level is used to disprove a theory.

Level of significance § Type 1 error – a researcher wrongly rejects the null

Level of significance § Type 1 error – a researcher wrongly rejects the null hypothesis, rather than retaining it, as level of significance is too low. § Type 2 error – a researcher wrongly retains the null hypothesis, rather than rejecting it, as level of significance is too high.

Recap Research Methods § Aims § Hypotheses § Experimental design § Selection of participants

Recap Research Methods § Aims § Hypotheses § Experimental design § Selection of participants and sampling techniques § Operationalisation of variables § Demand characteristics and investigator effects § Pilot studies § Reliability and validity § Control of extraneous § Ethical issues variables 71