Having a hard time getting the correct answer. Did this homework assignments 4 times and my answer is still wrong. Is it best to do it on excel ?

The pulse rates of 146 randomly selected adult males vary from a low of 39 bpm to a high of 119 bom. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 95% confidence that the sample mean is within 2 bpm of the population mean. Complete parts (a) through (c) below. a. Find the sample size using the range rule of thumb to estimate o. n= (Round up to the nearest whole number as needed.) b. Assume that o = 10.9 bpm, based on the value s = 10.9 bpm from the sample of 146 male pulse rates n= (Round up to the nearest whole number as needed.) c. Compare the results from parts (a) and (b). Which result is likely to be better? The result from part (a) is the result from part (b). The result from is likely to be better because