AP Statistics Unit 7

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Jordan wondered if the bean burritos at Restaurant A tend to be heavier than the bean burritos at Restaurant B. To investigate, she visited each restaurant at 10 randomly selected times, ordered a bean burrito, and weighed the burrito. The 95% confidence interval for the difference (A – B) in the mean weight of burrito is 0.06 ounce ± 0.20 ounce. Based on the confidence interval, which conclusion is most appropriate?

• Because 0 is included in the interval, there is convincing evidence that the mean weight is the same at both restaurants.

• Because 0 is included in the interval, there isn’t convincing evidence that the mean weight is different at the two restaurants.

• Because 0.06 is included in the interval, there is convincing evidence that the mean weight is greater at Restaurant A than Restaurant B.

• Because 0.06 is included in the interval, there isn’t convincing evidence that the mean weight is greater at Restaurant A than Restaurant B.

• Because there are more positive values in the interval than negative values, there is convincing evidence that the mean weight is greater at Restaurant A than Restaurant B.

A sample survey interviews SRSs of 500 female college students and 550 male college students. Researchers want to determine whether there is a difference in the proportion of male and female college students who worked for pay last summer. In all, 410 of the females and 484 of the males say they worked for pay last summer. Which of the following is the correct standard error for a test of the hypotheses?

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A researcher plans to conduct a significance test at the α = 0.01 significance level. She designs her study to have a power of 0.90 at a particular alternative value of the parameter of interest. The probability that the researcher will commit a Type II error for the particular alternative value of the parameter she used is

• 0.01

• 0.10

• 0.89

• 0.90

• 0.99

Which graph shows a line of best fit for the scatter plot?

• Graph A

• Graph B

• Graph C

• Graph D

What kind of correlation?

• Positive

• Negative

• No Correlation

What kind of correlation?

• Strong Positive

• Strong Negative

• Weak Negative

• Weak Positive

Which of the graphs would have a correlation coefficient of r = 0 ?

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Which of the graphs would have a correlation coefficient of r = 0.98 ?

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Which of the graphs would have a correlation coefficient of r = -0.97 ?

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