1) Let z be a normal random variable with mean 0 and standard deviation 1. The 4th decile of z is ___.

Question

a) 0.67 b) –1.25 c) -0.25 d) 1.28 e) 0.50

2) According to the central limit theorem, if a sample of size 50 is drawn from a population with a standard deviation of 10, the standard deviation of the distribution of the sample means would equal ___.

Answer 1

It would have to be negative and close to the mean.