## Pearson and Spearman correlation

### HW # 3

**5. You should use a ______ correlation when one or more of the variables are measured on an ordinal scale.
**

a. Pearson

b. Spearman

c. Point biserial

d. Any of these are appropriate.

**Answer: b. Spearman
**

**10. A statistics instructor required students to complete homework assignments prior to their taking an online statistics exam. After the students took the exam, he wanted to create a regression equation using students' total homework points to predict their scores on the exam. The SPSS output is below, what is the regression equation for this prediction?**

a. Y = .06 (X) + 4.21

b. Y = .727 (X) + 28.14

c. Y = .782 (X) + 28.14

d. Y = .727 (X) + 4.21

**Answer: b. Y = .727 (X) + 28.14
**

**12. In regression, the predictive contribution of each independent variable is represented by ______.
**

a. the partial slope

b. a β coefficient

c. the regression plane

d. a path coefficient

**Answer: a. the partial slope
**

**30. Which of these scatterplots is most likely to result in the regression equation Y′ = 2.25 – .45(X)?
**

a. Figure A

b. Figure B

c. Figure C

d. Figure D

**Answer: b. Figure B
**

**Explanation:
**

Q 5

**Spearman’s correlation coefficient is a measure to calculate the correlation between two Ordinal variables.
**

Q 10

**Coefficients are given in 3rd table “coefficients” under the heading unstandardized coefficients
**

Q 12

**Each partial coefficient gives the contribution of an independent variable in multiple regression.
**

Q 30

**In the first figure, the trend is increasing but the β coefficient is negative i.e. -0.45, but in the second figure the trend is decreasing which matches the requirement. Figure C represent increasing and decreasing trend both and Figure D is showing no trend at all.
**