Answer:
112
Step-by-step explanation:
Given that in a study of the stability of IQ scores, a large group of individuals is tested once at age 18 and again at age 35.
Age 18: average score = 100, SD = 15
Age 35: average score = 100, SD = 15, r = 0.80
Let us obtain regression equation of y on x.
Let y be the scores at age 35 and x at age 18
Slope =
The line passes through (100,100) being average of x and y
Hence regression line would be
a) Here given that x =115
Hence
the average score at age 35 for all the individuals who scored 115 at age 18, would be 112.
b) Prediction also would be the same 112.