Problem 16 in Chapter 11 described a study examining the effect of eating oatmea
ID: 2960484 • Letter: P
Question
Problem 16 in Chapter 11 described a study examining
the effect of eating oatmeal regularly on cholesterol.
Cholesterol was measured before and after adding
oatmeal to the diet of a sample of n 9 participants.
For this sample, cholesterol scores averaged MD 16
points lower with the oatmeal diet with SS 538 for
the difference scores. Use the data to estimate how
much effect oatmeal would have on the cholesterol
level for the general population. Make a point estimate
and a 95% confidence interval estimate of the
population mean difference.
Explanation / Answer
Given mean=16, s^2=SS/(n-1)=538/8= 67.25
a point estimate= 16
a=0.05, |t(0.025,df=n-1=8)|=2.31 (check student t table)
So 95% CI is
xbar±t*[s^2/n]
--> 16±2.31*sqrt(67.25/9)
--> (9.685531, 22.31447)