Stats Ch. 10

sampling distribution of a difference between two proportions

• Center

• Shape

• Spread

formula of pooled proportion

Normal condition for difference of proportions

Large counts - the counts of “successes” and “failures” in each sample or group are all at least 10

spread: standard deviation of sampling distribution of difference between two means

10% condition

each sample is no more than 10% of its population

Conditions for performing inference about µ1 - µ2

• SRS

• Independence

• Normal

Independence condition

When sampling without replacement, check that N₁ >= 10n₁ and N₂ >= 10n₂

Do not use two-sample t procedures if the graph shows strong skewness or outliers.

True

Significance tests for µ1 – µ2

H_a: µ1 – µ2 > hypothesized value

H_a: µ1 – µ2 < hypothesized value

H_a: µ1 – µ2 ≠ hypothesized value