Help A random sample of n measurements was selected from a population with unknown mean and standard deviation o = 30 for each of the situations in parts a through
d. Calculate a 95% confidence interval for foreach of these situations.
a. n=75, X = 25
b. n=250, x= 116
c. n = 90, X = 16
d. n=90, = 5.21
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.
a. (1.)
(Round to two decimal places as needed.)