Calculate the upper and lower limit for a 95% confidence interval about the mean in dollars and cents. (Note: do not round the standard error.)
A family wants to reduce its expenditures for personal items like gifts, newspapers, magazines and so forth. A sample of 49 months of receipts yields a mean of $220.00 with a standard deviation of $30.00. They decide to calculate a 95% confidence interval about this mean.
Standard error = (standard deviation)
÷
(square root of sample size)
Upper limit = $
Lower limit = $