A survey of several 10 to 12 year olds recorded the following amounts spent on a trip to the mall: $23.30, $22.29, $21.23, $21.86, $21.57 Construct the 80% confidence interval for the average amount spent by 10 to 12 year olds on a trip to the mall. Assume the population is approximately normal.
Calculate The sample mean for the given data.. Round your answer to two decimal places.
Calculate the standard deviation.. Round your answer to two decimal places.
Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
Construct the 80% confidence interval. Round your answer to two decimal places.