13.

Critical z scores separate

A)

correct and incorrect decisions.

B)

true and false hypotheses.

C)

valid and invalid samples.

D)

common and rare outcomes.

14.

Metal detectors at airports are used to determine whether passengers are carrying weapons. If the null hypothesis states that a passenger isn't carrying a weapon, a type II error would occur whenever

A)

a weapon-carrying passenger passes the detector and activates the alarm.

B)

a weapon-carrying passenger passes the detector without activating the alarm.

C)

a weapon-free passenger passes the detector without activating the alarm.

D)

a weapon-free passenger passes the detector and activates the alarm.

15.

When used appropriately, a one-tailed test is more

A)

descriptive.

B)

definitive.

C)

sensitive.

D)

precise.

16.

Given critical z values of 1.96 and an observed z value of -2.40, the appropriate decision is to

A)

neither retain nor reject, but conduct another investigation.

B)

retain the null hypothesis.

C)

reject the null hypothesis.

D)

neither retain nor reject, but increase the size of the sample.

17.

If it's important to detect even a relatively small effect, increase the

A)

size of the effect.

B)

scope of the investigation.

C)

retention region.

D)

sample size.

18.

Greek letters are used to describe characteristics of

A)

samples and sampling distributions.

B)

sampling distributions and populations.

C)

samples, sampling distributions, and populations.

D)

samples and populations.

19.

A random sample of 100 college students is taken from the student body of a large university. Each student estimates the number of hours spent studying each week. Therefore, the sampling distribution of the mean is

A)

equal to the population.

B)

centered about the sample mean.

C)

very compact.

D)

approximately normal in shape.