In: Math
A simple random sample of 60 items resulted in a sample mean of 70. The population standard deviation is = 15.
a. Compute the 95% confidence interval for the
population mean. Round your answers to one decimal place.
Enter your answer using parentheses and a comma, in the form
(n1,n2). Do not use commas in your numerical answer (i.e. use 1200
instead of 1,200, etc.)
b. Assume that the same sample mean was obtained from a sample of 130 items. Provide a 95% confidence interval for the population mean. Round your answers to two decimal places.
c. What is the effect of a larger sample size on the interval estimate?
Larger sample provides a - Larger or smaller - margin of error?