1) A test of very many students is modeled by a Normal Distribution. If the standard deviation is 10 and the sample mean E (X) = 75 calculate with a 2.5% confidence interval given that the hypothesis Ho = 80. Where we are assuming the following. Also for each of the following give the interval which yields confidence 2.5% 1) The sample size is 50 2) the sample size is 100 3) the sample size is 400