AP Statistics Inference for the Difference of Two Proportions Quiz: 10 Questions with Explanations

A No differenceB p2 is greater than p1C A convincing difference, with p1 greater than p2D The sample is biased

The interval is entirely positive, so 0 is not plausible and p1 is larger.

A About 0.011B About 0.989C About 0.021D About 0.5

Right tail 0.0107 doubled is 0.0214.

A 0.40B 0.35C 0.30D 0.70

(40 + 30)/(100 + 100) = 0.35.

A each group’s own sample proportionB the pooled proportionC p = 0.5 alwaysD the difference only

Intervals do not assume equality, so each sample’s p-hat is used.

A only p-hat1B only p-hat2C p = 0.5D the pooled proportion

H0 says there is one common proportion; pooling estimates it.

A not requiredB required for each groupC required for the pooled groupD replaced by n >= 30

With random assignment, independence comes from the randomization, not from sampling less than 10%.

A p1 is definitely greaterB 0 is a plausible value for the differenceC p2 is definitely greaterD the samples are dependent

An interval containing 0 means no convincing evidence of a difference.

A Compare before and after rates for the same 30 studentsB Compare 5 and 8 successesC Compare one sample with a known valueD Compare vaping rates in two independent random samples of teens

The samples must be independent and have enough successes and failures.

A a narrower intervalB a wider intervalC a larger p-hatD a larger alpha

Margin of error is z* times the standard error.

A fail to reject H0B reject H0C accept H0D increase the sample size

0.003 is less than 0.05, which is strong evidence against H0.