STATs. Please help me I am lost.

Question

A random sample of 100 felony trials showed a sample mean waiting time between arrest and trial = 173 days with a population standard deviation of waiting times = 28 days. Find a 99% confidence interval for the population mean waiting time.

n=100

x bar = 173

s= 28

CL= 99%

df= 99

I have the degrees of freedom as 99 but the chart in my textbook doesn't have a value for 99. I don't know what to do now.

Answer 1

You are given the population standard deviation. Therefore, you should use z statistics.