Suppose that X1, . . . , Xn form a random sample from the normal distribution with mean and variance 2, where both

Suppose that X1, . . . , Xn form a random sample from the normal distribution with mean μ and variance σ2, where both μ and σ2 are unknown. A confidence interval for μ is to be constructed with confidence coefficient 0.90. Determine the smallest value of n such that the expected squared length of this interval will be less than σ2/2.