When engaging in weight control (fitness/fat burning) types of exercise, a person is expected to attain about 60% of their maximum heart rate. for 20-year-olds, this rate is approximately 120 bpm. a simple random sample of 100 20-year-olds was taken, and the sample mean was found to be 107 bpm with a standard deviation of 45 bpm. researchers wonder if this is evidence to conclude that the expected level is actually lower than 120 bpm. to determine this, we test the following hypotheses:

h0 : ? = 120, ha : ? < 120

reference: ref 17-2

a 95% confidence interval for the population mean weight control heart rate, ? , of 20-year-olds is

answers

a.
107