The amount people who pay for electric service varies quite a bit, but the mean monthly fee is $168 and the standard deviation i
s $34. The distribution is not Normal. Many people pay about $90 in rural areas of the country and about $150 in urban areas of the country, but some pay much more. A sample survey is designed to ask a simple random sample of 1,200 people how much they pay for electric services. Let xbar be the mean amount paid. Part A: What are the mean and standard deviation of the sample distribution of xbar? Show your work and justify your reasoning. (4 points) Part B: What is the shape of the sampling distribution of xbar? Justify your answer. (2 points) Part C: What is the probability that the average electric service paid by the sample of electric service customers will exceed $170? Show your work. (4 points)
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Answer:
The answer is below
Step-by-step explanation:
The question is not complete, what are the coordinates of point Q and R. But I would show how to solve this.
The location of a point O(x, y) which divides line segment AB in the ratio a:b with point A at () and B(
) is given by the formula:
If point Q is at () and S at (
) and R(x, y) divides QS in the ratio QR to RS is 3:5, The coordinates of R is:
Let us assume Q(−9,4) and S(7,−4)