After a certain task, subjects' heart rates increase.We want to estimate the average heart rate in the population after the task. We take a sample of 25 observations and find that the average heart rate is 68 beats per minute and the unbiased estimate of the population standard deviation is 10.

• What is the interval such that, if we did the same experiment 100 times, we expect the population mean to fall within it 95 times?
• If you tested the hypothesis that the average heart rate in the population is 80 against the hypothesis that it is not equal to 80, and you could tolerate a 5% Type I error rate, what would you conclude?