Assignment: Negative Correlation Depression

Assignment: Negative Correlation Depression

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1. Identify and briefly describe the three criteria that help to define science.

2. Explain what a negative correlation between depression and self-esteem means.

3. Explain what deception and debriefing are. When it is acceptable to use deception in a research study?

4. Provide an example of a variable measured on a(n): nominal scale, ordinal scale, interval scale, and ratio scale.

5. If observers in a study disagree 35 times out of 90, what is the interrater reliability? Interpret this interrater reliability coefficient.

6. Explain the difference between naturalistic observation and laboratory observation, noting advantages and disadvantages of each.

7. Identify and briefly describe probability sampling versus nonprobability sampling.

8. Imagine that you are writing a survey on student perceptions of the food in the dining hall. Write one open-ended, one closed-ended, and one partially open-ended question concerning quality of the food in the dining hall.

9. What are the problems with the following survey questions?

• Do you agree that Americans should be more concerned with conserving fuel and reducing pollution from auto emissions?

• Do you favor reducing the outrageous number of administrators in the federal government?

• Most people believe that politicians are overpaid. Do you agree?

10. Calculate the mean, median, and mode for the following distribution of scores: 2, 2, 6, 9, 10, 11, 15, 17, 18, 20.

11. Explain the difference between qualitative and quantitative variables, noting the relationship of nominal, ordinal, interval, and ratio data to these terms.

12. For a hypothetical normal distribution of test scores, approximately 95% fall between 38 and 62, 2.5% are below 38, and 2.5% are above 62. Given this information, (a) the mode=_____ and (b) the standard deviation=_____.

13. Calculate s (standard deviation) and A.D. (average deviation) for the following sample: 2, 2, 6, 9, 10, 10, 15, 18, 18, 20.

14. Students in the psychology department consume an average of 5 cups of coffee per day with a standard deviation of 1.75 cups. The number of cups of coffee consumed is normally distributed.

• What proportion of students consume an amount equal to or less than 6 cups a day?

• How many cups would an individual at the 80th percentile drink?

15. In a recent study it was found that the correlation between self-esteem and depression was -.64. Tom interprets this to mean that low levels of self-esteem lead to high levels of depression and vice verse. How is top misinterpreting this data?

16. What is the third variable problem, and how does the partial correlation technique help with this problem? Does it completely solve the problem? Why or why not?

17. Calculate the Pearson product-moment correlation for the data below. X 3 4 2 1 Y 5 5 3 4

18. Explain when each of the correlation coefficients listed below should be used.

• Pearson product-moment correlation coefficient.

• Spearman rank-order correlation coefficient.

• point-biserial correlation coefficient

• phi coefficient

19. Assume that the regression equation for the relationship between SAT scores and IQ scores is y = 9 +.105x. What would you expect the IQ score to be for the following individuals, given their SAT scores? Individual SAT Score IQ Score Susan 850 Sally 1175 Sam 1225 Sean 1050

20. If a researcher decided to use the .01 level of significance rather that using the more conventional .05 level of significance, what type of error is more likely to be made? Why?

21. Identify when it would be appropriate to use a parametric versus a nonparametric test.

22. Explain how a one-tailed hypothesis differs from a two-tailed hypothesis.

23. Explain how Type I and Type II errors are related to false alarm and misses.

24. What are inferential statistics and how do they differ from descriptive statistics?

25. If weight in the general population is normally distributed with an average of 160 and a standard deviation of 20 pounds, what is the probability of selecting someone who weights 120 or less or 170 or more pounds?