AP Statistics Confidence Interval for Slope

Which confidence would result in a wider interval (assuming nothing else changed), 91% or 97%?

• 97%, z* is larger for higher confidence intervals

• 97%, the standard error is larger for higher confidence intervals

• 91%, z* is larger for lower confidence intervals

• 91%, the standard error is smaller for lower confidence intervals

What do we use to estimate unknown parameters?

• Hypothesis Test

• Confidence Interval

• Trig Identity

• Guess and check

• The slope decreased and the r² increased.
• The slope increased and the r² decreased.
• The slope decreased but r² remained the same.
• Both slope and r² remained the same.

Raoul performed an experiment using 16 windup rubber band single-propeller airplanes. He would up the propeller a different number of times and recorded the amount of time (in seconds) that the airplane flew for each number of rotations that the propeller was wound. Which of the following is a 95 percent confidence interval for the slope of the regression line that relates the number of rotations to the plane's flight time?

• 0.0462 ± (2.145)(0.01565)

• 0.924 ± (2.145)(0.6413)

• 0.0462 ± (2.96)(0.01565)

• 0.924 ± (2.96)(0.6413)

• 0.0462 ± (2.131)(0.01565)

• A

• B

• C

• D

• E

Park rangers are interested in estimating the weight of the bears that inhabit their state. The rangers have data on weight (in pounds) and neck girth (distance around the neck in inches) for 10 randomly selected bears. Here is some computer output from a linear regression analysis of these data. Which of the following represents a 95% confidence interval for the slope of the population least-squares regression line relating the weight of a bear and its neck girth, assuming the conditions for inference are met?

Which of the following changes to a study would result in a narrower confidence interval?

• increasing the confidence level, increasing the sample size

• decreasing the confidence level, decreasing the sample size

• increasing the confidence level, decreasing the sample size

• decreasing the confidence level, increasing the sample size.

• t-interval for slope

• one-sample t-interval for μ

• one-sample t-interval for p

Conditions for _____________?

• t-test or t-interval for slope

• chi-square test

• one-sample z-test and z-interval for p

• two sample z-test and z-interval for µ₁-µ₂

• one sample t-test and t-interval for μ

• t-interval for slope

• one-sample t-interval for μ

• one-sample t-interval for p