12. The pulse rates of 157 randomly selected adult males vary from a low of 45 bpm to a high of 105 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume...

12. The pulse rates of 157 randomly selected adult males vary from a low of 45 bpm to a high of 105 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 90​% confidence that the sample mean is within 4 bpm of the population mean. Complete parts​ (a) through​ (c) below.

Find the sample size using the range rule of thumb to estimate

σ.

n=____

​(Round up to the nearest whole number as​ needed.)