Statistics for the Sciences Roger N. Morrissette, PhD Homework Assignment Lesson
ID: 3053127 • Letter: S
Question
Statistics for the Sciences Roger N. Morrissette, PhD Homework Assignment Lesson Eight nt nk A research interested in the study habits of college freshman computed a correlation coefficient between the average number of hours a student spends watching television each day and his or her SAT verbal score. The correlation coefficient and the means and standard deviations are listed in the table below. Use this information to answer Problems 1-5. M Daily Hours Spend Watching Television (x) 2.7 SAT I 471 Mean Standard Deviation Correlation Coefficient 0.125 9433 0.943 1. What is the predicted daily hours spent watching television of a student who has an SAT verbal score of 600? a. 1.91 hours. b. 3.42 hours c. 0.58 hours. d. 1.03 hours. what is the standard error of the estimate for the predicted value in #1? a. 1.45 b. 0.123 c. 0.042 d. 0.211 2.Explanation / Answer
for regression x=a+by=8.59-0.0125y
b=r*sd(x)/sd(y)=-0.943*0.125/9.433=-0.0125
a=mean(x)-b*mean(y)=2.7-(-0.0125)*471.5=8.59375
(1) answer d.1.03
for y=600 x=8.59-0.0125*600=1.09
nearest choice is d.1.03
(b)answer is c.
SE=sqrt((1-r*r)*var(x))=sqrt((1-(-0.943)*(-0.943))*0.125*0.125))=0.0416
nearest choice is c.0.042