n order to estimate the average electric usage per month, a sample of 44 houses were selected and the electric usage determined. The sample mean is 2,000 KWH. Assume a population standard deviation of 133 kilowatt hours. At 99% confidence, compute the upper bound of the interval estimate for the population mean.

Answer: 2051.64 kilowatt hours.Step-by-step explanation:Given : Sample size : 44The sample mean :  [tex]\overline{x}=2,000\text{ KWH. }[/tex]Population standard deviation: [tex]s\igma= 133\text{ KWH. }[/tex]z-value for 99% confidence interval : [tex]z_c=2.576[/tex]The upper bound of the 99% confidence interval estimate for the  population mean :-[tex]\overline{x}+z_c\dfrac{\sigma}{\sqrt{n}}[/tex][tex]2000+(2.576)\dfrac{133}{\sqrt{44}}\\\\=2000+(2.576)(20.05)\\\\=2000+51.6488=2051.6488\approx2051.64[/tex]Hence, the  upper bound of the 99% confidence interval estimate for the population mean = 2051.64 kilowatt hours.