James is a fitness instructor. He wants to know if attending a training session

increases the productivity of people. James knows that the mean productivity

of people in the population is 66 with a standard deviation of 12. James took asample of 100 workers and gave them all the training session. After training,

the mean productivity was 68. He then compared the mean productivity of the sample to the mean for the population. Use= .05.

What samples mean should you expect if the null hypothesis is true?