The Energy Star rating system is an energy efficiency program run by the U.S. Environmental Protection Agency (EPA). Energy Star certified appliances, such as televisions and refrigerators, are rated in regard to their average energy consumption per year. A certain brand of Energy Star certified refrigerator is stated to have a mean yearly electricity cost of $119. A consumer advocacy organization believes that this claim is wrong, that the energy consumption of this particular refrigerator is different than $119 per year. The group collected a random sample of 20 refrigerators of the model in question and had each lab-tested for electricity consumption. The yearly energy consumption of each is given below.

119.53	118.04	119.88	119.18	118.06	119.56	118.5	119.39	119.56	118.18
118.39	119.19	119.39	119.8	119.63	119.58	119.09	119.91	119.5	119.14

Using a significance level of 1%, test the hypothesis that the average yearly electricity consumption of the refrigerator in question is different than $119 per year. Assume that the distribution of all electricity costs of this model of refrigerator is approximately normally distributed. Use the p-value method. State the null and alternative hypothesis for this test. H0:H0:? = > < p = p p p p > p < H1:H1:? = > < p = p p p p > p < Determine if this test is left-tailed, right-tailed, or two-tailed.

• two-tailed
• left-tailed
• right-tailed

Should the standard normal (zz) distribution or Student's (tt) distribution be used for this test?

• The Student's tt distribution should be used
• The standard normal (zz) distribution should be used

Determine the test statistic for the hypothesis test. Round the solution to four decimal places. Determine the p-value (range) for the hypothesis test.

• p-value < 0.001
• 0.001 < p-value < 0.01
• 0.01 < p-value < 0.02
• 0.02 < p-value < 0.05
• 0.05 < p-value < 0.10
• 0.10 < p-value < 0.20
• p-value > 0.20

Determine the appropriate conclusion for this hypothesis test.

• The sample data provide sufficient evidence to reject the alternative hypothesis that the mean electricity cost per year of this model refrigerator is different than $119 and thus we conclude that the mean yearly electricity cost of this refrigerator is likely $119.
• The sample data provide sufficient evidence to reject the null hypothesis that the mean electricity cost of this model refrigerator is $119 per year and thus we conclude that it is likely the true mean electricity cost per year is different than $119.
• The sample data do not provide sufficient evidence to reject the null hypothesis that the mean electricity cost of this model refrigerator is $119 per year and thus we conclude that it is likely the true mean electricity cost per year is $119.
• The sample data do not provide sufficient evidence to reject the alternative hypothesis that the mean electricity cost per year of this model refrigerator is different than $119 and thus we conclude that the mean yearly electricity cost of this refrigerator is likely different than $119.