AP Statistics : Estimation

Study concepts, example questions & explanations for AP Statistics

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Example Questions

Example Question #61 : Ap Statistics

Jim calculated a  confidence interval for the mean height in inches of boys in his high school. He is not sure how to interpret this interval. Which of the following explains the meaning of  confidence.

Possible Answers:

More information is needed.

There is a  chance that Jim's interval contains the true mean height.

 of boys' heights fall with the interval Jim calculated.

 of all possible sample means fall within Jim's interval.

In the long run,  of all confidence intervals calculated from the same population will contain the true mean height.

Correct answer:

In the long run,  of all confidence intervals calculated from the same population will contain the true mean height.

Explanation:

95% confidence means that the methods Jim uses to calculate his confidence interval give him correct results 95% of the time. It does not mean that there is a 95% chance that the true mean will be inside the interval. It also does not mean that 95% of all heights or possible sample means fall within the interval.

Example Question #2 : Confidence Intervals And Regression

The number of hamburgers served by McGregors per day is normally distributed and has a mean of  hamburgers and a standard deviation of  Find the range of customers served on the middle  percent of days. 

Possible Answers:

Correct answer:

Explanation:

First, find the first quartile of the distribution.

Then, find the third quartile of the distribution. 

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