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:

The coordinate plane where the point is 1 unit to the left and 3.5 units down

Step-by-step explanation:

On a coordinate plane the negative side is left and down and positive is up and right so you can eliminate any answer with up or right. The point says its (-1,-3.5) which means it will be 1 to the left making it -1 and 3.5 down which will make it -3.5.