AP Stats and Power

Hint: think logically...

• A

• B

• C

• E

Hint: For regression, you are estimating two things...how does that affect the degrees of freedom?

• A

• B

• D

• E

To test a claim about a mean, when the population standard deviation is unknown we use:

• z procedures

• Pythagorean Theorem

• t procedures

• np > 10 and n(1-p) > 10

When p-value is greater than alpha we:

• Accept Ho

• Accept Ha

• Fail to reject Ho

• Reject Ho

Margin of error equals:

• Critical Value ∗ standard Error

• z*

• 1.96

• Standard Error

If the correlation coefficient r=.78, what percentage of variation in y is explained by variation in x?

• 61%

• 44%

• 39%

• 78%

A telephone survey of 400 registered voters showed that 256 had not yet made up their minds 1 month before the election. How sure can we be that between 60% and 68% of the electorate were still undecided at that time?

• 2.4%

• 64.0%

• 90.5%

• 95.3%

The scores of the math portion of the SAT are approximately normal with a mean of 510 and a standard deviation of 42. Approximately what percent of students will score higher than 600?

• 0.9838

• 0.0162

• 0.0179

• 0.9821

The average high temperature in July for a midwest city is 89 degrees. What is the standard deviation if 15% of July's on record for the city have an average high temperature above 91.5 degrees? Assume average temperatures are normally distributed.

• s = 0.060

• s = 16.667

• s = 0.416

• s = 2.404

95% of students who take the AP stats exam need between 186 and 214 minutes to complete it. What is the standard deviation of time students need to finish the exam? Assume times are normally distributed.

• 4.67 minutes

• 14 minutes

• 7 minutes

• 28 minutes