Answer
Standard Deviation = 1.3 and Mean = 21.1
Work Step by Step
-Find the Least-Squares Line by obtaining the slope and the intercept.
-The Slope = r(SDy/SDx). Plug the given values in to get a slope of -.71199.
-The intercept is =Ymean - b1(xmean). Ymean is given as 23.642, xmean is 11.5, and we just bound b1. 23.642 + .71199(11.5) = 31.82.
-Now plug in intercept and slope to formula to get Y= 31.82 - .71199x.
-x is 15, so formula yields 21.1 as the mean
-SD^2= SS(RESIDUAL)/n-2. n=12, and SS(RESID) is given as 16.7812, so SD^2 =1.678, so SD = 1.3
