Answer: 
Step-by-step explanation:
Given : Sample size of healthy adults: n= 106
Degree of freedom = df =n-1 = 105
Sample mean body temperature : 
Sample standard deviation : 
Significance level ; 
∵ population standard deviation is unknown , so we use t- critical value.
Confidence interval for the population mean :

Using t-distribution table , we have
Critical value for df = 105 and
= 
A 99% confidence interval estimate of the mean body temperature of all healthy humans will be :






Hence, a 99% confidence interval estimate of the mean body temperature of all healthy humans = 