Question

the u.s. energy information administration claimed that u.s. residential customers used an average of 10,176 kilowatt hours (kwh) of electricity this year. a local power company believes that residents in their area use more electricity on average than eia's reported average. to test their claim, the company chooses a random sample of 122 of their customers and calculates that these customers used an average of 10,559kwh of electricity last year. assuming that the population standard deviation is 2756kwh , is there sufficient evidence to support the power company's claim at the 0.05 level of significance? step 2 of 3 : compute the value of the test statistic. round your answer to two decimal places.

Answer 1

To test the power company's claim, conduct a hypothesis test and calculate the test statistic using the provided formula.

Step-by-step explanation:

To test the power company's claim, we can conduct a hypothesis test. Let's define the null hypothesis (H0) as the claim that the average electricity usage in the power company's area is the same as the average usage reported by the U.S. Energy Information Administration (EIA). The alternative hypothesis (Ha) would be that the average usage in the power company's area is higher than the EIA average.

To calculate the test statistic, we can use the formula: z = (sample mean - population mean) / (population standard deviation / sqrt(sample size)). Plugging in the values, we get: z = (10559 - 10176) / (2756 / sqrt(122)). Calculating this will give us the value of the test statistic.