The mean and the standard deviation of a random sample of n measurements are equal to 33.4 and 3.7, respectively.
a. Find a 90% confidence interval for µ if n= 144
b. Find a 90% confidence interval for µ if n= 576
c. Find the widths of the confidence intervals found in parts a and b.
What is the effect on the width of a confidence interval of quadrupling the sample size while holding the confidence coefficient fixed?