Suppose that the random variable X represents the amount of electrical energy used (in kwH) in a month for residents in Virginia. The historical amount of electrical energy used in a month for residents is 102 kwH. The following data (in kwH per month) were recorded from a random sample of 8 residents: 111 113 145 105 90 100 150 88(a) Calculate the mean and sample variance of X. (b) What is t statistic with this problem?

a)

b)

And if we replace we got:

Step-by-step explanation:

Part a

For this case we have the following data: 111 113 145 105 90 100 150 88

We can calculate the mean with the following formula:

And replacing we got:

And the sample variance can be calculated with this formula:

And replacing we got:

Part b

For this case we want to check is the true mean is equal to 102 or no, the t statistic is given by:

And if we replace we got:

step-by-step explanation:

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