Alex's times for running a mile are Normally distributed with a mean time of 5.28 minutes and a standard deviation of 0.38 seconds. Chris's times for running a mile are Normally distributed with a...

Extracted text: Alex's times for running a mile are Normally distributed with a mean time of 5.28 minutes and a standard deviation of 0.38 seconds. Chris's times for running a mile are Normally distributed with a mean time of 5.45 seconds and a standard deviation of 0.2 seconds. Ten of Alex's times and 15 of Chris's times are randomly selected. Let i, -i, represent the difference in the mean times for Alex and Chris. Which of the following represents the standard deviation of the sampling distribution for i,-? 0.09 0.13 0.17 0.18