Answer:
Step-by-step explanation:
Given that a researcher, using data on class size (CS) and average test scores (ATS) from 100 third grade classes, estimate the OLS regression
ATS = 520.4 - 5.82 times CS,
R^2 = 0.8,
SER = 11.5
a) If class size =20
ATS = [tex]520.4-5.82(20)\\= 520.4 - 116.4\\=404[/tex]
b) When CS increases from 19 to 21 i.e. 2 units ATS increases by 2(slope)
= 11.64 units
c) Here n=100, mean CS = 21.4
So Sample average test score = [tex]520.4-5.82(21.4)\\= 359.852[/tex]
d) Sample std deviation = std dev/sqrt of 100
=1.15