A typical washing machine has several different cycles, including soak, wash, and rinse. The energy consumption of a washing machine is linked to the length of each cycle. A random sample of 21 washing machines was obtained, and the length (in minutes) of each wash cycle was recorded. The summary statistics arex=37.8 andS =5.9. Assume the underlying distribution of main wash cycle times is normal.

Fill in the blanks. (Give your answers to four decimal places.)

A 95% confidence interval for the true mean wash cycle time is(,).