A biologist examines 17 water samples for nitrate concentration. The mean nitrate concentration for the sample data is 0.822 cc/cubic meter with a standard deviation of 0.0018 Determine the 80% confidence interval for the population mean nitrate concentration. Assume the population is approximately normal.

Step 1 of 2:

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