Question 930112
Sample: n = 31, mean = $56,  s = $6.35 
a) Estimated population mean = $56
b) ME =2.576(6.35/sqrt(31) = 2.94
CI: $56±2.94,    (53.06, 58.94)
c) n = (1.96(6.35)/2)^2 = 19.7580,   20 sample size (Always go to next Integer)