Correlations Some people say that older people get

Correlations Some people say that older people get more beautiful with age? Carol Vorderman aged 25 Carol Vorderman aged 49

Is there a Correlation? 20 years 30 years 40 years 50 years 60 years

50 perfect people were asked about how attractive they thought the following people were and they gave their ratings below – plot this on a graph Rating: 2 20 years Rating: 4 30 years Rating: 6 40 years Rating: 8 50 years Rating: 10 60 years

50 negative people were asked about how attractive they thought the following people were and they gave their ratings below – plot this on a graph Rating: 10 20 years Rating: 8 30 years Rating: 6 40 years Rating: 4 50 years Rating: 2 60 years

What do you think – note your rating for the ages and then plot it on the graph 20 years 30 years 40 years 50 years 60 years

What are Correlations? Learning Objectives 1. Identify the features of correlations. 2. Outline differences between positive and negative correlations and no correlations. 3. Outline features of a correlation coefficient. Prep for Friday 8/11/19 Correlations Exam Style Questions

fozzy on facebook Hello ! I am fozzy bear and we are going to look at facebook today Yay !!!

It’s all about friends – right ? • OK – so here is my Facebook page and lets all agree about one thing; • Facebook is all about friends – right ? • The more friends you have – the happier you will be : o)

It’s all about friends – right ? • That means there is a positive correlation between friends and happiness. • A correlation is a relationship between two variables where changes in one variable go along with changes in the other variable. • So back to facebook: the more friends you have – the happier you will be : o) 9

There are 2 types of correlations Negative Variable Y Positive Variable X 10

Number of Friends Positive Correlations • Positive Correlation: • The variables change in the same direction, • Like friends and happiness. Happiness

• Negative Correlation: • The variables change in opposite directions • As friends increase, loneliness will decrease. Number of Friends Negative Correlations Loneliness

The Coefficient of Correlation • If you were reporting your research you couldn’t just say “the line slopes up to the right a bit” or “it looks positive” • There is a mathematical value for any correlation. • We call this the coefficient of the correlation.

• A coefficient of 0. 00 means there is no relationship between the variables. • If we compared the number of friends people have to the % mark they got in their year 7 French exam, we might find there was just no connection. • Sally got 70% and Billy got 30% but they both have 120 friends This is a zero folks !

The Coefficient of Correlation • A value of +1. 00 means a perfect, positive correlation. • The more hours you work – the more money you get. • If there is a 100% correspondence between the two, then the correlation would be +1. 00 • [We all know one whole one is 100% right ? ] B W Johnson August 2012 15

The Coefficient of Correlation • A value of -1. 00 means a perfect, negative correlation. • The more money you spend – the less you have in the bank. • There could be a 100% negative correlation between spending and saving. 16

In the real world you don’t often find perfect correlations, usually they are weaker. • If I say there is a +0. 4 correlation between the number of friends people have on Facebook and the number they have in real life. • How could that be? 17

In the real world you don’t often find perfect correlations, usually they are weaker. • If there was a – 0. 7 correlation between the time spent on facebook and the time spent on homework – why is it not -1. 0 ? 18

Strengths and Weaknesses 3 advantages of correlations: 2 disadvantages • They may indicate a connection • They do not prove a causal relationship. between 2 issues in situations • They do not reflect where experimental proof is curvilinear impossible. relationships • They do not require manipulation of variables and are therefore safer and more ethical than doing experiments on humans. • High ecological validity – these numbers came from real life 19

Problems with Correlations (1) • Correlations show linear relationships but do not reflect curvilinear ones – so for example the effect of stress on exam performance : But really it’s a curve Exam Mark Correlation shows it as a straight line. Stress 20

Problems with Correlations • Correlations demonstrate that there may be a relationship between two sets of data. • But they dont show what the cause is !!! • You have to try to work out the relationship. • Don’t fall for the trap of thinking that one aspect automatically causes the other. • Suppose I find a correlation between shoe size and the number of facebook friends ? • Does that mean that one of them causes the other? I don’t think so 21

The “third variable” problem Does violent crime make people buy more ice-cream? Does eating ice-cream cause violent crime ? Or is there a “Third Variable” which is causing both ? Violent crime Oh my ! What could that third variable be? Ice cream sales 22

Why not causation? A B Maybe A causes B B A Or maybe B causes A A But something else might cause both. C B X A Y B Or the two things might not be related at all 23

Does facebook improve A Level grades? A B Maybe increased use of facebook is pushing up grades B A Or maybe better educated students use facebook more A C B But maybe more access to computers has improved A level grades AND led to more people using facebook. Or the two things might not be related at all. C A More online access has boosted facebook D B Better teaching pushes up grades.

Group Activity • Do a simple scattergraph and correlation line on the whiteboard using these two items of data: – The time you go to bed. – The time you get out of bed in the morning. • Is your group correlation positive or negative ? • Try doing a separate correlation for males and one for females. Is there much difference?

Do you know…? • Jay Belskey found that children who spent too many hours per week in nursery care were more aggressive later – what kind of correlation is that ? 26

Classwork questions • If teenagers have more Facebook friends than old people does that prove they are more friendly? • Is the correlation between time spent on Facebook and % marks in exams likely to be positive or negative. 27

Slightly more difficult • If we found a strong positive correlation between high levels of aggression and the hormone testosterone, which would be the independent variable. • In scientific terms, what is wrong with this sentence: • “Research has found a correlation level of 64. 7 between watching violent movies and committing crimes, proving once and for all that such films damage children. ”

What are Correlations? Correlations Correlation: a measure of how strongly two or more variables are related to each other: • Height is positively correlated to shoe size • The taller someone is, the larger their shoe size tends to be. • Like Self Report and Observation, there is no manipulation of data, conditions or groups in correlations. • No IV or DV, just to co-occurring variables (co-variables). Stretch & Challenge: If there is no independent (controlled) variable, what can’t we establish?

What are Correlations? • Still use the sampling methods: –self selected, random, snowball, opportunity • Still consider the same ethical issues: –How many of the ethical issues can you identify? (C. D. W. P)

• Unlike experiments there is no CONTROLLED or INDEPENDENT variable, just two variables that occur together as ‘co-variables. ’ • As there is no IV to manipulate we cannot establish cause and effect. • We don’t know which variable is causing the other, we just know there is a relationship between them. Experiment CAUSE EFFECT IV DV

• Unlike experiments there is no IV, just two variables that occur together as ‘co-variables. ’ • As there is no IV to manipulate we cannot establish cause and effect • We don’t know which variable is causing the other, we just know there is a relationship between them. Correlation Co. V ? Co. V NO CAUSE & EFFECT

Aims and hypotheses What is the difference between the aim of a study and the experimental hypothesis? The aim of a study describes its purpose. For example, the aim of Loftus & Palmer (1974) could have been: “to investigate whether leading questions can alter people’s memory of a car crash”. The hypothesis is a testable statement about what will happen. It is more precise than the aim. The hypothesis of Loftus & Palmer (1974) could have been: “participants that hear the word ‘smashed’ will estimate that the cars were travelling faster than participants that hear ‘contacted’”.

Aim or Hypothesis? To investigate whether we find it easier to Students will remember significantly The number of letters recalled by women To investigate howshort gender affects Gender will affect term memory Gender will not affect short term will be greater than the number recalled more numbers than letters short term memory capacity remember letters or numbers capacity for letters capacity for numbers bymemory men

Writing hypotheses There are two types of experimental hypothesis: directional and non-directional. There is also the null hypothesis. A directional hypothesis predicts the direction of any differences in the way people behave. For example, a directional hypothesis would predict that participants who eat chocolate before a test will achieve a significantly higher score than those participants who do not.

Writing hypotheses A non-directional hypothesis predicts a difference in the way people behave but not which direction this will be in. For example, a non-directional hypothesis would predict there will be a significant difference in participants’ test scores depending on whether they eat chocolate before the test or not. A null hypothesis predicts that the independent variable will have no effect on the dependent variable. For example, a null hypothesis would predict that there will be no significant difference in participants test scores depending on whether they eat chocolate or not.

Writing hypotheses Null hypothesis = H 0 Alternate hypotheses • Directional (aka 1 tailed) H 1 • Non-directional (aka 2 tailed) H 2

Identify the hypotheses

Starter Task What are the 4 types of research method? C. O. S. E.

Starter Task 2# cognitive area

Starter Task 2 # for individual differences area

Starter Task 3 measures of dispersion around the mean (S. V. R)

Starter Task 2# biological area

Starter Task What are the 4 types of sampling method? R. O. S. S.

Starter Task 2 # for psychodynamic area

Starter Task 2# social area

Starter Task 3 # develop –mental area

Starter Task 3 types of hypothesis (N. D. N. )

Starter Task 3 debates in Psychology

Starter Task 3 measures of central tendency (M. M. M. )

Testing Hypotheses To write a testable hypothesis you need to identify: The independent variable (IV), which is the variable that is changed by the experimenter. The dependent variable (DV), which is the variable that is measured by the experimenter. For example, when studying the effect of caffeine on test performance the IV would be caffeine intake and the DV would be test score. If you have trouble remembering which variable is which, imagine you are the experimenter. Think of the IV as something I change. Think of the DV as being like DIY – it needs lots of measuring.

IV and DV

IV and DV: Which one is the IV? Which is the DV? Birth order (being oldest / middle / The older you are, the more likely you Newspapers will describe older people TV will show women as are to oppose the legalisation of youngest) affects the types of brands as more honest than younger people cannabis you buy weaker than men

Variables

Variables

Operationalising Once psychologists have created a hypothesis, they must define the independent and dependent variables so that they are measurable. This is called operationalizing. Consider this hypothesis: Memory will be better in the morning than in the afternoon. How could memory be operationalized? Memory (the DV) could be operationalized as how many numbers a person can hold in their STM (their digit span). 7, 5, 2, 9, 1, 6…

Variables If we want to study the effects of alcohol on behaviour; – What is the independent variable? – What is the dependent variable? What behaviours could we investigate? BWJ August 2012 23 plus activities 58

Quick Test: Key Terms 1=H 2=F 3=G 4=E 5=A 6=B 7=C 8=D

Practice Row 1 = Beevors Row 2 = Kennedys Row 3 = Leemans Row 4 = Mc. Gills Row 5 = Paulls Row 6 = Ridings Stretch and Challenge = Row 7&8

Correlations can be both the primary method or secondary technique Self reports and observations can both be used as a way to gather data on variables, and then see if there is a relationship between them. • Experiments can compare the data between two groups using correlations. • men have a stronger correlation between age and time spent looking in the mirror than women. Primary method: Correlations Secondary technique: Self report/Observation Primary method: Experiment Secondary technique: Correlation Stretch and Challenge: which core study uses experiment as the method and correlation as the technique?

Independent Work Task • Identify other possible correlations we could investigate for age and sleep. • Extension: Identify any two variables you would find interesting to investigate

Positive and negative correlations • Positive Correlation: as one variable increases, so does the other. • Negative Correlation: as one variable increases, the other decreases. • No Correlation: there is no relationship between the variables. Stretch and Challenge: The more revision is done, the higher the final grade is. Is this a positive or negative correlation?

Positive, negative and no correlations • Perfect Positive Relationship • No relationship • Perfect Negative Relationship

Starter Task: Correlation or Causation https: //www. psychologytoday. com/blog/the-truisms-wellness/201510/can-your-birthdaypredict-your-mental-health

Starter Task: Correlation or Causation

Positive, negative and no correlations

Correlations: Scatter diagrams and Hypotheses Learning Objectives • Identify the features of scatter diagrams. • Outline the different correlation hypotheses. • Evaluate the strengths and weaknesses of correlations.

Correlation Co-efficient • We can measure the strength of the relationship, by using inferential statistics. • Which statistical test would we need to use? Why? • Being wealthy is correlated with living longer, BUT eating healthily and exercising has a stronger relationship with living longer. • Correlation Coefficient: a number between -1 and 1 that tells us how strong the relationship is.

Correlation Co-efficient +1. 0 perfect positive correlation +0. 8 strong positive correlation +0. 5 moderate positive correlation +0. 3 weak positive correlation 0 no correlation -0. 3 weak negative correlation -0. 5 moderate negative correlation -0. 8 strong negative correlation -1. 0 perfect negative correlation

Scatter diagrams • We can display correlation data in scatter diagrams. • One variable (amount of revision done) along one axis and another variable (final grade) along the other. • Each ‘point’ on the scatter diagram represents one participant: how much revision they put in and what their final grade was.

Amount of revision (in hours) Grade achieved A*-U Amount of revision (in hours) 0 2 5 7 10 Final grade U E C B A*

Amount of revision (in hours) Grade achieved A*-U • We can then use the scatter diagram to describe the relationship between the variables

Scatter diagrams

Hypotheses • Unlike Observation and Self Report we can generate hypotheses for Correlation Research. • Recap: Null Hypothesis Alternate hypothesis (one tailed or two tailed). What is the difference between a one tailed and a two tailed hypothesis?

Hypotheses • Correlations can’t show cause and effect • Can’t mention the effect one variable will have on the other so we talk about the ‘relationship’ between two variables • Still using the term significant • Still must clearly state the variables and how they have been operationalised • NEVER using the words cause, effect or difference.

Hypotheses • Null hypothesis: there will be no relationship There will be no significant relationship between V 1 and V 2. • Alternate hypothesis: One tailed: There will be a significant positive/negative relationship between V 1 and V 2 Two tailed: there will be a significant relationship between V 1 and V 2. Which word(s) must you NEVER use in a correlational hypothesis?

Hypotheses Which word(s) must you NEVER use in a correlational hypothesis? http: //w ww. buzzf eed. com /kjh 2110 /the-10 mostbizarrecorrelati ons

Correlations http: //w ww. buzzf eed. com /kjh 2110 /the-10 mostbizarrecorrelati ons

Evaluation • Our correlation shows that ice-cream sales are positively correlated with murder rates. • Do we think buying ice-cream causes people to commit murder? • What third factor might make people more likely to buy ice creams and more likely to be angry and get in fights? • Why would it be a problem not to consider alternative variables? • Where in society do we tend to see correlationships described in causal terms?

Practice Page 6

Strengths of Correlations Makes a good pilot study to generate a hypothesis for an experiment. ü Can research variables that would be unethical to manipulate. ü Can understand the relationship between two variables (positive/negative, weak/strong).

Weaknesses of Correlations do not show causation. They have the same weakness as whatever method was used to gather the data (observation/self report). Tell us nothing about other variables that may be the real cause Often correlations are misleading: NEVER USE DIFFERENCE, EFFECT OR CAUSE when describing a correlation.

Positive or Negative Correlation Positive Correlation Negative Correlation https: //quizlet. com/205572164/ocrpsychology-mathematical-skills-flash-cards/

Positive or Negative Correlation A student who has many absences has a decrease in grades. As a child grows, so does his clothing size. As a person’s level of happiness decreases, so does his level of helpfulness.

Positive or Negative Correlation As a tadpole gets older, its tail gets smaller. As more people go to the movies, the amount of money spent on tickets increases. As snowfall totals increase, the amount of people driving decreases.

Positive or Negative Correlation As the slope of a hill increases, the amount of speed a walker reaches may decrease. As weather gets colder, air conditioning costs decrease. If a train increases speed, the length of time to get to the destination decreases.

Positive or Negative Correlation If it is darker outside, more light is needed inside. If the sun shines more, a house with solar panels requires less use of other electricity. The faster a jet pilot flies, the higher the G-forces are. The further one runs, the slower one’s pace may be.

Positive or Negative Correlation The longer amount of time you spend in the bath, the more wrinkly your skin becomes. The longer your hair grows, the more shampoo you will need. The more alcohol one consumes, the less judgment one has. The more it rains, the more sales for umbrellas go up.

Positive or Negative Correlation The more one smokes cigarettes, the fewer years she will have to live. The more one works, the less free time one has. The more time you spend running on a treadmill, the more calories you will burn. The older a man gets, the less hair that he has. When workers get a raise, morale improves. https: //create. kahoot. it/#quiz/12950 f 7 d-45 e 24284 -8 b 32 -d 0 e 837816720