Suppose x has a normal distribution with = 1.2. (a) Find the minimal sample size required

Question:

Suppose x has a normal with σ = 1.2.
(a) Find the minimal sample size required so that for a 90% confidence interval, the maximal margin of error is E = 0.5.
(b) Based on this sample size and the x can we assume that the is approximately normal? Explain.
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...