AP Statistics Intro to Hypothesis Testing

A car manufacturer advertises that its new subcompact models get 47 mpg. If μ is the mileage of these cars, what could be the null and alternate hypothesis if we wanted to check if the car's mpg is overrated?

• H₀ = 47
  H_a = 47

• H₀ = 47
  H_a < 47

• H₀ = 47
  H_a > 47

• H₀ = 47
  H_a ≠ 47

If a sample mean is in the critical region with alpha level 0.05, it would still (always) be in the critical region if alpha were changed to 0.01?

• False

• True

H₀: μ = k

H₁: μ > k

• Left-tailed test

• Right-tailed test

A __________ occurs if you reject the null hypothesis when it is true.

• Type I error

• Type II error

A manufacturer claims that his tires last at least 40,000

miles. A test on 25 tires reveals that the mean life of a tire

is 39,750 miles, with a standard deviation of 387 miles.

Test the Manufacturer’s claim at α = .01.

• Reject Ho

• Reject Ha

• Fail to reject Ho

• Fail to reject Ha

In testing hypotheses, which of the following would be strong evidence against the null hypothesis?

• using a small level of significance

• using a large level of significance

• obtaining data with a small p-value

• obtaining data with a low test statistic

A __________ occurs if you accept the null hypothesis when it is false.

• Type I error

• Type II error

A level of significance of 5% means:

• There's a 5% chance we're wrong

• There's a 5% chance we'll be wrong if we fail to reject the null hypothesis

• There's a 5% chance we'll be wrong if we reject the null hypothesis.

• There's a 5% chance you'll get an A on the test.

A fast food outlet claims that the mean waiting time in

line is less than 1.9 minutes. A random sample of 20

customers has a mean of 1.7 minutes with a standard

deviation of 0.8 minute. If α = 0.05, test the fast food

outlet's claim using P-values.

• Reject Ho

• Reject Ha

• Fail to reject Ho

• Fail to reject Ha

A fast food outlet claims that the mean waiting time in line is less than 3.5 minutes. A random sample of 20 customers has a mean of 3.7 minutes with a standard deviation of 0.8 minute. If α = 0.05, test the fast food outlet's claim.

• Reject Ho

• Reject Ha

• Fail to reject Ho

• Fail to reject Ha