A survey of several 9 to 11 year olds recorded the following amounts spent on a trip to the mall: $20.60, $16.44, $10.80, $13.86, $21.22, $10.65, $20.34 Construct the 95% confidence interval for the average amount spent by 9 to 11 year olds on a trip to the mall. Assume the population is approximately normal. Copy Data Step 3 of 4: Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.