A researcher collated data on Americans’ leisure time activities. She found the mean number of hours spent watching television each weekday to be 2 point 7 hours with a standard deviation of 0 point 4 hours. Jonathan believes that his football team buddies watch less television than the average American. He gathered data from 15 football teammates and found the mean to be 2 point 3 Which of the following shows the correct z -statistic for this situation?