MonthKwH
Oct 075628
Nov 075293
Dec 076042
Jan 08NA
Feb 089708
Mar 085191
Apr 085930
May 084582
Jun 085262
Jul 083857
Aug 085013
Sep 085118

# MS 150 Statistics q08 "Part IV": Hypothesis Testing • Name:

The director of maintenance sent out the following note to all faculty and staff:

We are once again calling your attention to energy conservation. Attached is the Kilo Watt Hour usage report per building for your reference. At the current cost per KwH the college will be paying \$46,410.00 per month or \$556,920.00 per year. (91,000 KwH x \$.51=\$46,410x per month x 12= \$556,920.00). As you can see, the college needs everyone's assistance in conserving energy. Thank you for you understanding and cooperation.

The table includes the kilowatt-hours used by the south faculty building F2. For the twelve months prior to the data in the table F2 used an average of 6094.33 KwH per month (data). Use the data in the table to generate a 95% confidence interval and determine whether the south faculty building has used more energy, less energy, or the same amount of energy over the last twelve months. Use as the pre-existing, previously known population mean μ energy consumption 6094.33 KwH.

1. __________ What level of measurement is the data?
2. x = __________ What is the sample mean x?
3. n = __________ Find the sample size n for the data.
4. sx = __________ What is the sample standard deviation sx?
5. __________ What is the point estimate for the population mean μ implied by the sample data?
6. df = ___________ How many degrees of freedom are there?
7. tc = ____________________ Calculate the value of tcritical
8. SE = ____________________ Calculate the standard error of the sample mean x.
9. E = ____________________ Calculate the margin of error E for the sample mean x.
10. Calculate the 95% confidence interval for the population mean μ based on the sample data.

p(__________ ≤ μ ≤__________) = 0.95

Given the following hypotheses:
Null hypothesis: H0: μ = 6094.33 KwH
Alternate hypothesis: H1: μ ≠ 6094.33 KwH

1. α = _________ Given a confidence level of 95%, what will be the value of alpha α?
2. __________ Based on the confidence interval above, is the difference between the known population mean μ and the sample mean x statistically signficant?
3. ________________________________________ Would we reject the null hypothesis or fail to reject the null hypothesis at the α recorded above?
4. __________ Did the south faculty building F2 use a statistically significantly lower amount of energy?