PSYC 355 Correlation

PSYC 355 Correlation Liberty University

1. If the following seven scores are ranked from smallest (#1) to largest, what rank should be assigned to a score of X = 6? Scores: 1, 1, 3, 6, 6, 6, 9
2. What correlation is obtained when the Pearson correlation is computed for data that have been converted to ranks?
3. A researcher measures IQ and weight for a group of college students. What kind of correlation is likely to be obtained for these two variables?
4. A set of n = 5 pairs of X and Y values has SSX = 16, SS Y = 4 and SP = 2. For these data, what is the Pearson correlation?
5. A researcher obtains a Pearson correlation of r = 0.60 for a sample of n = 6 pairs of X and Y scores. If the researcher tests the significance of the correlation, what value will be obtained for the t statistic?
6. For a group of graduating college seniors, a researcher records each student’s rank in his/her high school graduating class and the student’s rank in the college graduating class. Which correlation should be used to measure the relationship between these two variables?
7. Three main characteristics of a correlation coefficient include all of the following except:
8. A researcher records the age and price for a group of used Hondas. What kind of correlation is likely to be obtained for these two variables?
9. What is indicated by a positive value for a correlation?
10. Suppose that there is a correlation of r = 0.41 between the amount of time that each student reports studying for an exam and the student’s grade on the exam. This correlation would mean that there is a tendency for people who study more to get better grades.
11. The value obtained for the sum of products, SP, determines the sign (+/–) for the Pearson correlation.
12. A researcher obtains SSX = 20, SSY = 5, and SP = 7 for a set of n = 25 pairs of scores. The Pearson correlation for these scores is r = 7/10 = 0.70.
13. If people are classified by age (over 30/under 30) and by political affiliation (Democrat/Republican), then the point-biserial correlation would be the proper technique to measure the relationship between the two variables.
14. The sign of the correlation (+/–) is generally meaningless for the point-biserial correlation and the phi-coefficient.
15. For a two-tailed hypothesis test evaluating the significance of a correlation, the null hypothesis states that the sample correlation is zero.