only the 2 circled questions.I need tutor Bolla to help with these questions

56)
Solution (a):
Given,
The population standard deviation is given, therefore, we use the standard normal distribution < Use Z table for 5% level of significance = 1.96>
The required confidence interval lies between (96.828, 99.572). With 95% confidence, we can conclude that the population mean lies between the above mentioned lower and upper bound.
Solution (b):
Using the conversion of normal distribution to standard normal distribution,
The required probability is calculated as:

Therefore, 50% of the individuals would be expected to have body temperature more than 98.6F.
Solution (c):
The coolest 20% of all the individuals are located till:

< Values are taken from the...