A survey of several 10 to 13year olds recorded the following amounts spent on a trip to the mall:

$28.64 ,$24.42, $19.35, $22.14

Construct the 95%confidence interval for the average amount spent by 10to 13 year olds on a trip to the mall. Assume the population is approximately normal.

1. Calculate the sample mean for the given sample data. Round your answer to two decimal places.

2. Calculate the sample standard deviation for the given sample data. Round your answer to two decimal places.

3. Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

4. Construct the 95%confidence interval. Round your answer to two decimal places.