Answer:
5.503484≤x≤9.116516
Step-by-step explanation:
The formula for calculating the CI is expressed as;
CI = x±z*s/√n
x is the mean= 7.31
z is the 99% z-score = 2.58
s is the standard deviation = 6.26
n is the sample size = 80
Substitute into the formula
CI = 7.31± 2.58*6.26/√80
CI = 7.31± 2.58*6.26/8.94
CI = 7.31± (2.58*0.7002)
CI = 7.31±1.806516
CI = (7.31-1.806516, 7.31+1.806516)
CI = (5.503484, 9.116516)
Hence the 99% confidence interval for the population mean is
5.503484≤x≤9.116516
