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.