Find an 80% confidence interval for the heart rates of US adults over 25 if a sample of size 15 is SAR from the male population. The sample yields an average rate of 69.9 beats per minute. The...

Find an 80% confidence interval for the heart rates of US adults over 25 if a sample of size 15 is SAR from the male population. The sample yields an average rate of 69.9 beats per minute. The standard deviations for the samples is 3.5 beats per minute. Assume heart rates in humans are normally distributed.