Suppose we wish to have a probability of at least 1 - a that the
error in estimating µ by Xis no more than d in magnitude. For
large n, we have
We wish the statement P(IX - µ] <>
(a) Assuming a, d, and a are known, show that a sample of size
n = ((cr/d)Za/2 )2 will satisf'y the requirements.
(b) Suppose IQ scores have a = 15 and we wish to estimate the
true average IQ of a large group using X. If we wish a
maximum absolute error of 3 with probability 0.95, what
sample size is required?
(c) If we wish the maximum error to be 1.5 with probability
0.95, what sample size is required?