Average electric usage was studied. A previously known population standard deviation was 450 KWH. A sample of 81 houses was studied and found to have a mean of 1858 KWH.
Find the 95% confidence interval for the true mean.© BrainMass Inc. brainmass.com December 15, 2022, 7:50 pm ad1c9bdddf
The formula for a proportion confidence interval is:
mean ± z * standard deviation / square ...
The 95% confidence interval for the true mean is determined.