Objective 91715 Today we will practice sampling applying

Objective: 9/17/15 Today we will practice sampling & applying concepts of statistics by completing an M&M Lab. Agenda: 1. 2. 3. 4. Take out homework Do Now-practicing IV & DV Notes M&M Lab

Research Methods - Statistics

★ How do psychologists ask & answer questions? Last time we asked that we were discussing ‘Research Methods. ’ ★ This time we will look at the data. ★ Stats is all about data.

★ Distinguish the difference between the purposes of descriptive & inferential statistics. ★ Discuss the value of reliance on operational definitions & measurements in behavioral research. ★ Statistical procedures analyze & interpret data & let us see what the unaided eye is missing.

★ Meaningful description of data is important in research. ★ Misrepresentation can lead to incorrect interpretation.

Descriptive Statistics Use measures of central tendency: mean, median and mode Use measures of variation: range and standard deviation

Mean, Median, Mode, & Range Mean, median, and mode are three kinds of "averages. " The MEAN is the “average” you're used to, where you add up all the numbers and then divide by the number of numbers. The MEDIAN is the “middle” value in the list of numbers. To find the median, your numbers have to be listed in numerical order, so you may have to rewrite your list first. The MODE is the “most” often occurring value. If no number is repeated, then there is no mode for the list. The RANGE is the “difference” between the largest and smallest values.

The mean is the usual average, so: (13 + 18 + 13 + 14 + 13 + 16 + 14 + 21 + 13) ÷ 9 = 15 Note that the mean isn't a value from the original list. This is a common result. You should not assume that your mean will be one of your original numbers. Joe Di. Maggio was the AL MVP and had a batting avg of. 357 in 1941. He also had an amazing 56 game hitting streak that is still a record.

The median is the middle value, so I'll have to rewrite the list in order: 13, 13, 14, 16, 18, 21 There are nine numbers in the list, so the middle one will be the (9 + 1) ÷ 2 = 10 ÷ 2 = 5 th number: 13, 13, 14, 16, 18, 21 So the median is = 14

13, 13, 14, 16, 18, 21 The mode is the number that is repeated more often than any other, so the mode= 13 The largest value in the list is 21, and the smallest is 13, so the range is. . . 21 – 13 = 8. What is the mean? mean = 15 median? median = 14 mode? mode = 13 range? range = 8 In real life, suppose a company is considering expanding into an area and is studying the size of containers that competitors are offering. Would the company be more interested in the mean, the median, or the mode of their containers? Answer: the mode because they want to know what size tends to sell most often.

A Skewed Distribution How are the results “skewed”? ? ? Is the mean the best indicator of family income? ? Probably not. That’s because of the outliers - $710, 000 is one such example above. So range & standard deviation come into play to help be more of an accurate description of these statistics.

Measures of Variation Range: The difference between the highest and lowest scores in a distribution. Standard Deviation: Average difference between each score and the mean. LARGE SD: More spread out scores are from the mean. SMALL SD: More scores bunch together around the mean.

M&M Lab for Sampling & Statistics 1. 2. Follow each step on the lab Do not eat the candy until you are done!

Objective: Today we will examine correlational studies & explore the measures of central tendency & measures of variation. Agenda: Do Now Notes Activity

Do Now: Turn & Talk Abdul has volunteered to participate in an experiment evaluating the effectiveness of aspirin. Neither he nor the experimenters know whether the pills he takes during the experiment contain aspiring or are merely placebos. The investigators are apparently making use of: a. Naturalistic observation b. Illusory correlation c. The double-blind procedure d. Random sampling e. The overconfidence effect Explain how you came up with the correct answer.

How do you calculate Standard Deviation? Good News - you will NEVER have to on a test. However, I want you to understand what it represents, so here you go! Which of the following sets of data have the GREATEST SD? 1, 5, 7, 30 5, 10, 12, 18 30, 32, 34, 35 How did you figure this out? ? ★ Can estimate SD by looking at the “spread” of #s ★ Can you find mean and compare each # to the mean

Standard Deviation Normal Distribution: A distribution of scores that produces a bell-shaped symmetrical curve. In this “normal curve” - the mean, median, and mode fall exactly at the same point. The span of ONE SD on either side of the mean covers approximately 68. 2% of the scores in a normal distribution. ➔ Average IQ = 100 ➔ Most people (68. 2%) fall into 85115 range ➔ IQ extremes are above 130 and below 70

Normal Curve <---50%---> You need to write this in your notes, copy it down, & memorize it. Period. There is no other way to do it. 1 SD from the mean = 68. 27% 2 SD from the mean = 95. 43% 3 SD from the mean = 99. 73% 4 SD from the mean = 99. 994%

You. Tube: Schallhorn on Standard Deviation

A Skewed Distribution Remember this? Wouldn’t this skew the curve? Is “mean” the best indicator of family income? ? Probably not. That’s because of the outliers $710, 000 is one such example above. So range & standard deviation come into play to help be more of an accurate description of these statistics.

A Skewed Distribution: Negative vs. Positive - Majority of scores above the mean. One or few extremely LOW scores force the mean to be less than the median score. + Majority of scores below the mean. One or few extremely HIGH scores force the mean to be greater than median score.

A Skewed Distribution How are the results “skewed”? ? ?

Inferential Statistics: Involves estimating what is happening in a sample population for the purpose of making decisions about that population’s characteristics (based in probability theory). Basically, inferential stats allow us to say: “If it worked for this population, we can estimate it will work for the rest of the population. ” ie - Drug Testing -- if the meds worked for the sample, we estimate they will have the same effect on the rest of the population. There is always a chance for error in whatever the findings may be, so the hypothesis & results must be tested for significance.

Inferential Statistics Statistical Significance - difference observed between 2 groups is probably NOT due to chance. The difference instead is likely due to a real difference between the samples. Data is “significant” when the likelihood of a difference being due to chance is less than 5 times out of 100. In other words. . . There is a 95% chance (or greater) likelihood that any difference seen is due to your independent variable shown numerically as p <. 05 Important because if research is statistically significant it means that the results are probably not a fluke or due to chance.

Inferential Statistics Null Hypothesis - States that there is NO difference between 2 sets of data. (basically the opposite of your hypothesis!) Null Hypothesis = Opposite Hypothesis Purpose. . . Until the research SHOWS (by proving the original/alternative hypothesis) that there is a difference, the researcher must assume that any difference present is due to chance. In other words, not due to statistical significance.

Inferential Statistics Null Hypothesis Type I Error: Reject the null (choosing the original hypothesis), yet the null is actually true. Type II Error: Accept the null, yet the original hypothesis is actually correct. **You don’t want to have errors! But, you could make them. Truth About Population Decision Researcher Makes NULL TRUE NULL FALSE** REJECT NULL (ACCEPT ORIGINAL) Type I Error Correct Decision ACCEPT NULL Correct Decision Type II Error ** If NULL FALSE - then the regular hypothesis is true!

Inferential Statistics Null Hypothesis Example Original Hypothesis: “A bomb threat was called into the front office, so we need to evacuate the school. ” Null Hypothesis: “There is no bomb in the school, so we do not need to evacuate. ” Truth About Population ** If NULL FALSE - then the regular hypothesis is true! Decision Researcher Makes REJECT NULL (ACCEPT ORIGINAL) ACCEPT NULL TRUE NULL FALSE** Type I Error - students evacuated, yet bomb squad does not find a bomb. Erred on side of caution. Correct decision. Students evacuated, bomb squad finds bomb & safely removes it. All are safe! Correct decision. No evacuation, no bomb. Threat ignored & students stay in class safe and sound. Type II Error - Bomb threat is ignored. Students stay in class, bomb goes off & students are injured.

Non-Experimental Research: Methods for Examining Information Descriptive Statistics Correlation = strength of a relationship between two variables ● ● Positive vs. Negative Correlations = nature of relationship Coefficient of Correlation = strength of relationship CORRELATION DOES NOT EQUAL CAUSATION

Correlation Scatterplots

Establishing Cause-Effect Relationships *Inferring that one variable causes change in another variables requires: Demonstration that levels of the two variables changed together Demonstration that the cause preceded the effect Assurance that all other plausible causes have been ruled out ● ● ●

Ethics in Research

1. Introduction to ethics in research you must accept the responsibility to behave ethically toward those who will be affected by your research ethics is the study of proper action research ethics concerns the responsibility of researchers to be honest and respectful to all individuals who may be affected by their research studies or their reports of the studies’ results ● ● ●

ethical issues must be considered at each step in the research process ● ● ● what measurement techniques may be used for certain individuals how researchers select individuals to participate in studies which research strategies and designs may be used with certain populations and behaviors how studies may be carried out with individuals how results are reported The basic categories of ethical responsibility ● ● ● responsibility to the human and nonhuman individuals who participate in the research study responsibility to the discipline of science

2. Ethical issues and human participants in research Historical highlights of treatment of human participants ● ● World War II – brutal experiments performed on prisoners in Nazi concentration camps 1947 Nuremberg trial with experimenters who conducted those experiments as a result of that trial – Nuremberg Code has been established ● ● 10 guidelines for the ethical treatment of human participants in research Nuremberg Code laid the groundwork for the ethical standards that are in place today for both psychological and medical research

2. Ethical issues and human participants in research Historical highlights of treatment of human participants (cont. ) ● ● additional examples of maltreatment of human participants ● ● in 1963 unsuspecting patients have been injected with live cancer cells in 1972 400 men had been left to suffer with syphilis long after a cure was available

2. Ethical issues and human participants in research Historical highlights of treatment of human participants (cont. ) ● ● Milgram obedience study (Milgram, 1963) ● ● subjects instructed to use electric shock to punish other individuals when they made errors in a learning task participants were administering what appeared to be dangerously strong and painful shocks no real shocks were used in the study although the participants in this study sustained no physical harm, they suffered shame and embarrassment for having behaved inhumanely toward their fellow human beings

2. Ethical issues and human participants in research American psychological association (APA) Guidelines ● ● ● www. apa. org/ethics/code. html APA Ethics Code contains ten ethical standards, and you should be completely familiar with all of them before beginning any research with human participants

2. Ethical issues and human participants in research American psychological association (APA) Guidelines (major ethical issues) ● ● No harm ● the researcher is obligated to protect participants from physical or psychological harm ● ● ● Psychological harm – participants may feel increased anxiety, anger, lower self-esteem especially in situations where they feel that they have been cheated or insulted any risk of harm must be justified participants must be informed of any potential risks

2. Ethical issues and human participants in research American psychological association (APA) Guidelines (major ethical issues) ● ● Informed consent ● ● human participants should be given complete information about the research and their role in it they should understand the information and then voluntarily decide whether or not to participate ● ● ● information – if not possible to provide the subject with information about the purpose of the study we can explain to him at least exactly what will be done understanding – some participants may not be competent to understand the research (e. g. children), therefore, it is necessary to provide the information to a parent or a guardian voluntary participation – participants decide to participate of their own free will (no obligation because of a teacher or a professor asked them to do so)

2. Ethical issues and human participants in research American psychological association (APA) Guidelines (major ethical issues) ● ● deception – informed consent can not be obtain before the study ● ● ● to obtain unbiased results researchers must sometimes use deception because participants may adjust their own levels of performance in an attempt to satisfy the experimenter Passive deception (or omission) is the withholding or omitting of information (researcher intentionally does not tell participants some information about the study) Active deception (or commission) is the presenting of misinformation about the study to participants (misleading participants about the specific purpose of the study)

2. Ethical issues and human participants in research American psychological association (APA) Guidelines (major ethical issues) ● ● guidelines for a study involving deception: ● ● ● the deception must be justified in terms of some benefit that outweighs the risk to the participants the researcher can not conceal from the participants any significant aspects of the study that is expected to cause physical pain or severe emotional stress the researcher must provide the participant with debriefing that explains the true nature of the experiment, including the use and purpose of deception after the study is completed

2. Ethical issues and human participants in research American psychological association (APA) Guidelines (major ethical issues) ● ● Confidentiality ● ● is the practice of keeping strictly secret and private the information or measurements obtained from an individual during a research study Anonymity ● is the practice of ensuring that an individual’s name is not directly associated with the information or measurements obtained from that individuals (e. g. using codes)

The Institutional Review board (IRB) ● ● ● most human-participant research must be reviewed and approved by a group of individuals (scientists and nonscientists) not directly affiliated with the specific research study the U. S. Department of Health and Human Services (HHS) requires review of all human-participant research conducted by government agencies and institutions receiving government funds IRB typically requires that researchers submit a written research proposal that addresses each of the seven criteria of IRB (minimization of risk to participants, reasonable risk in relation to benefits, equitable selection, informed consent, documentation of informed consent, data monitoring, privacy and confidentiality) ● ● ● Category I (exempt review) – anonymous survey on innocuous topic Category II (expedited review) – minimal risk to participants Category III (full review) – special populations, deception, intervention, invasive measurement

3. Ethical issues and nonhuman subjects in research the first ethical question is whether nonhuman subjects should be used at all in behavioral research ●APA guidelines for the use and treatment of nonhuman subjects in research ● ● ● www. apa. org/science/anguide. html animals must be treated humanely, qualified individuals must conduct research, the research must be justified and the researcher has a responsibility to minimize discomfort or harm institutions that conduct research with animals have an animal research review board called the Institutional Animal Care and Use Committee (IACUC) ● ● Committee consists of a veterinarian, at least one scientist experience in animal research and a one member of public with no affiliation with the institution