Suppose that X1,..., Xn is a random sample from a n(, 2) population. a. If 2 is

Suppose that X1,..., Xn is a random sample from a n(μ, σ2) population.
a. If σ2 is known, find a minimum value for n to guarantee that a .95 confidence interval for n will have length no more than σ/4.
b. If σ2 is unknown, find a minimum value for n to guarantee, with probability .90, that a .95 confidence interval for n will have length no more than σ/4.