Kayla Greene is a team lead for an environmental group for a certain region. She is investigating whether the population mean mo
nthly number of kilowatt hours (kWh) used per residential customer in the region has changed from 2006 to 2017. She is concerned that changes such as more efficient lighting and the increased use of electronics and air conditioners are affecting the population mean monthly number of kilowatt hours consumed per residential customer. Kayla investigates the data and assumes the population standard deviation for 2006 and 2017 using the data that were provided to her by local utility companies. Using data that were collected by h company, Kayla selects a random sample of residential customers who were active for all of 2006 nd a separate sample of residential customers who were active for all of 2017. The population standard deviations and the results from the samples are provided in the accompanying table. Let A be the population mean monthly number of kilowatt hours consumed per residential customer in 2006 and jug be the population mean monthly number of kilowatt hours consumed per residential customer in 2017. What type of test is this hypothesis test? 2006 1 894.7kWh 1 361 σ,-193. 1 kWh 2017 910.2kWh n424 | σ2-182.9 kWh
Select the correct answer below:
A. This is a left-tailed test because the alternative hypothesis is H,: Ha 0.
B. This is a left-tailed test because the alternative hypothesis is H. μ. μ2 < 0.
C. This is a two-tailed test because the alte 0 This is a right-tailed test because the alternative hypothesis is H.: μ' μ'>0.
D. This is a right-tailed test because the alternative hypothesis is H, rnative hypothesis is Ha : μ. 142 /0
