Chapter 9, Section 1, Exercise 020 Inference on the Slope of Facebook Friends an
ID: 3312974 • Letter: C
Question
Chapter 9, Section 1, Exercise 020 Inference on the Slope of Facebook Friends and the Brain Computer output for a regression line to predict the number of Facebook friends a student will have, based on a normalized score of the grey matter density in the areas of the brain associated with social perception and associative memory is given below. Data for the sample of n 40 students are stored in FacebookFriends. Pearson correlation of GMdensity and FBfriends = 0436. P-Value 0.005. The regression equation is FBfriends = 367 + 82.4 GMdensity. Predictor Coef SE Coef TP Constant 366.64 26.35 13.92 0.000 GMdensity 82.45 27.58 2.99 0.005 S=165.716 R-Sq = 19.0% R-Sq(adj)=16.9% 800 700 600 500 400 300 200 100 -1 0 GMdensityExplanation / Answer
a) b1 =82.45
std error =27.58
b)
test statistic t=2.99
p value =0.005
conclusion reject Ho
c)
for n-2=38 degree of freedom and 99% CI ; crtiical t =2.7116
therefore 99% confidence interval =estimated slope -/+ t*Std error = 7.67 ; 157.23