Statistical Significance

1. Statistical Significance • Statistical Significance is a P score, which tells you that the difference between two scores, the scores of the experimental & control groups, could not have happened by chance • Essay hint: always define statistical significance as “could not have happened by chance.”

2. Operational Definitions • What is the Operation Definition of Sex (college students – freshman) 2% 3% 14% 40% 81% 99%

3. Review: Random Sample • For the population of the sex survey, if only 20 were chosen out of the freshman, they would represent the entire population • For a sample to be random, each member of the population has to have an equal chance of being drawn • REMEMBER: samples DO NOT have to be equally balanced by race, gender, intelligence, socioeconomics, etc – they just need to be random

4. Review: Correlation Coefficients • The number gives you the strength of the relationship • The sign gives you the direction • +1 or (-1) is a 100% lock in the relationship (all or none) • 0 = no relationship exists, not predictive • Rule of Thumb: anytime a coefficient exceeds .2 or (-.2) a relationship exists; .5 (-.5) or higher is a very strong relationship • Sex survey: probably around a .95, meaning that I can predict if you’re a teen, you think intercourse is sex

5. Review: Positive and Negative Correlation Coefficients • The more antioxidants you take, the lower your cancer rate. • Antioxidants go up • Cancer goes down • NEGATIVE CORRELATION • The more you exercise, the happier you are • Positive correlation

6. Visual…

8. Problems with Surveys • Wording effects • Halo Effect • Sample Size • 5 Hour Energy

9. Flaws in Evaluating Research • Sampling Bias • Historically, psychologists tend to UNDER sample minorities and non-western cultures • Sample composition of studies from APA journal found that 68% of samples came from United States, 27% from Europe or English speaking countries, with 5% from the remainder of the world • US counts for less than 5% of the world’s population

10. Placebo Effect • Participant’s expectation lead them to experience some change even though they receive empty, fake, or ineffectual treatment • Experiments on effects of alcohol

11. Distorted Self-Reporting • Social desirability bias: tendency to give socially approved answers to questions about oneself • Response Set: tendency to respond to questions in a particular way that is unrelated to content of the questions • Halo effect: overall evaluation of a person, object, or institution spills over to influence more specific ratings

12. Experimenter Bias • Occurs when a researcher’s expectations or preferences about the outcome of a study influence results obtained • We see what we want to see • Sway participants with nonverbal cues

13. How to neutralize experimenter bias • Double blind procedure: neither participants nor experimenters know which subjects are in the experiment and which are in control group • Only useful in between subject designs

14. Ethics Psychological research relies on the use of deception and the use of animals This is where the ethical dilemmas lie Concern for possible inflicting harm on participants

15. Deception • Participants often misinformed of purpose of study to reduce problems resulting: • Placebo effects • Unreliability of self reporting • Psychologists have faked fights, rapes, thefts, muggings, fainting, epileptic seizures, breakdowns, etc • Participants have been led to believe that they were hurting others with electric shocks, had homosexual tendencies, overhearing negative comments about themselves, etc

16. Perception of Deception • Critics will say that deception causes distress in participants • Empirical data will show that participants enjoy the experience after the fact and that they didn’t mind being misled • Researchers are more concerned about negative effects than participants

17. Benefit of Deception based experiments • Researchers defend that it would be unethical to NOT conduct effective research on human behavior and social issues • Today, institutions that conduct research have ethics committees that must evaluate research proposals prior to experiment

18. Animal Research • Used to see connection between human and animal behavior • Used for experiments that would be clearly unacceptable to test with human subjects • Relationship to deficient malnutrition during pregnancy and birth defects

19. Controversy • Is it ethical to subject animals to pain/unnecessary cruelty for research experiments? • Do animals have the same rights as humans? • PETA (People for the Ethical Treatment of Animals) • 1984: 8,000 members • 2003: 750,000 members

20. American Psychological Association Research Ethics • Take care to do no long or short-term psychological damage to subjects; protect them from harm. • Obtain informed consent • Confidentiality • You may deceive your subject, but are required to let them in on the experiment as soon as possible and to discuss the ramifications of their actions.

21. APA Guidelines for Research - Humans • Participation is voluntary and people are allowed to withdraw at any time • Participants will not be subject to harmful or dangerous experiments • If participants are subject to deception, they will be informed of nature and purpose of study ASAP • Participants right to privacy should never be compromised

22. APA Guidelines for Research - Animals • Harmful or painful procedures cannot be justified unless the benefits of research are substantial • Research animals are entitled to decent living conditions