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(*explaining how to do this, step by step; while how to compute this with a TI-8

ID: 3330809 • Letter: #

Question

(*explaining how to do this, step by step; while how to compute this with a TI-84, if possible/ applicable please)

In a climate survey, it was determined that in a random sample of 19 days, the average temperature in Kalamazoo at 2:00 PM in the months of July and August is 79.31 degrees with a standard deviation of 3.073 degrees. Using this information, a 95% confidence interval for the average is (77.829, 80.791). Which of the following is the appropriate interpretation of this interval?

Question 3 options:

1)

We are 95% confident that the proportion of all days' temperatures will fall between 77.829 and 80.791.

2)

We are 95% confident that the average daily temperature for the months of July and August at 2:00 PM is between 77.829 and 80.791.

3)

We are certain that 95% of the days in the months of August and July will have a temperature at 2:00 PM between 77.829 and 80.791.

4)

We are 95% confident that the average daily temperature for the months of July and August at 2:00 PM for the days recorded is between 77.829 and 80.791.

5)

We cannot determine the proper interpretation of this interval.

1)

We are 95% confident that the proportion of all days' temperatures will fall between 77.829 and 80.791.

2)

We are 95% confident that the average daily temperature for the months of July and August at 2:00 PM is between 77.829 and 80.791.

3)

We are certain that 95% of the days in the months of August and July will have a temperature at 2:00 PM between 77.829 and 80.791.

4)

We are 95% confident that the average daily temperature for the months of July and August at 2:00 PM for the days recorded is between 77.829 and 80.791.

5)

We cannot determine the proper interpretation of this interval.

Explanation / Answer

right choice is second

2)

We are 95% confident that the average daily temperature for the months of July and August at 2:00 PM is between 77.829 and 80.791.

To interpret a confidence interval remember that the sample information is random - but there is a pattern to its behavior if we look at all possible samples. Each possible sample gives us a different sample estimate and a different interval. But, even though the results vary from sample-to-sample, we are "confident" because the margin-of-error would be satisfied for 95% of all samples .

2)

We are 95% confident that the average daily temperature for the months of July and August at 2:00 PM is between 77.829 and 80.791.