The sampling distribution of x-bar is Normal with mean and standard deviation (SE) = / n (when population Normal or n is large) These facts make inferences about possible Example: Let X represent Weschler adult intelligence scores: X ~ N(100, 15). Take an SRS of n = 10 SE = / n = 15/10 = 4.7 xbar ~ N(100, 4.7) 68% of sample mean will be in the range SE = 100 4.7 = 95.3 to 104.7