A random sample of n measurements was selected from a population with unknown mean u and standard deviation o = 30 for each of the situations in parts a through d. Calculate a 90% confidence interval...

Extracted text: A random sample of n measurements was selected from a population with unknown mean u and standard deviation o = 30 for each of the situations in parts a through d. Calculate a 90% confidence interval for u for each of these situations. %3D a. n= 50, x= 22 b. n= 200, x= 115 c.n=110, x= 18 d.n= 110, x= 5.02 e. Is the assumption that the underlying population of measurements is normally distributed necessary to ensure the validity of the confidence intervals in parts a through d? Explain. %3D a. OD) (Round to two decimal places as needed.)