AP Stat inference procedures identification

Are people who have pets more likely to be left-handed than people who don't have pets?

• one-sample z test for a proportion

• one-sample z interval for a proportion

• two-sample z test for the difference of proportions

• two-sample z intervalfor the difference of proportions

Answer explanation

This is a yes/no question, so a test is required rather than an interval. There are two separate populations: people who have pets vs people who don't, so a two-sample test is needed.

What percentage of students at a certain university live on campus?

• one-sample z test for a proportion

• one-sample z interval for a proportion

• two-sample z test for the difference of proportions

• two-sample z interval for the difference of proportions

Answer explanation

The question asks for the value of the proportion, so an interval is needed rather than a test. There is only one population: students at the university.

Do the majority of YouTube channels have at least 10 videos?

• one-sample z test for a proportion

• one-sample z interval for a proportion

• two-sample z test for the difference of proportions

• two-sample z interval for the difference of proportions

Answer explanation

Since this is a yes/no question, we need a test rather than an interval. There is only one population: YouTube channels.

How much more likely are teenagers to use TikTok compared to people over the age of 20?

• one-sample z test for a proportion

• one-sample z interval for a proportion

• two-sample z test for the difference of proportions

• two-sample z interval for the difference of proportions

Answer explanation

The question asks for the size of the difference, so an interval is needed rather than a test. There are two separate populations: teenagers and people over the age of 20.

How much more do NFL players weigh compared to NBA players, on average?

• one-sample t test for a mean

• one-sample t interval for a mean

• two-sample t test for the difference of means

• two-sample t interval for the difference of means

Answer explanation

The question asks for the difference in the average weights, so an interval is required. There are two populations: NFL players and NBA players.

What's the average ad revenue of YouTube channels?

• one-sample t test for a mean

• one-sample t interval for a mean

• two-sample t test for the difference of means

• two-sample t interval for the difference of means

Answer explanation

An interval is needed because the question asks for the value of the average, and there is only one sample: YouTube channels.

Is the average daily high temperature higher in June or July in a certain city?

• one-sample t test for a mean

• one-sample t interval for a mean

• two-sample t test for the difference of means

• two-sample t interval for the difference of means

Answer explanation

A yes/no question requires a test, not an interval. There are two separate populations: the days in the month of June and the days in the month of July.

Do the students at a certain university spend more than twenty hours per week on classwork, on average?

• one-sample t test for a mean

• one-sample t interval for a mean

• two-sample t test for the difference of means

• two-sample t interval for the difference of means

Answer explanation

This is a yes/no question that requires a test, not an interval. There is only one population: students at the university.

Is there a relationship between favorite color and favorite type of food?

• chi-square test for goodness of fit

• chi-square test for independence

• chi-square test for homogeneity

• t test for regression slope

Answer explanation

The question asks whether there is a relationship between two categorical variables: favorite color and favorite type of food. In other words, are these two variables independent of each other?

Is the religious affiliation distribution among students at a certain university different from the 2020 census?

• chi-square test for goodness of fit

• chi-square test for independence

• chi-square test for homogeneity

• t test for regression slope

Answer explanation

There is one categorical variable: religious affiliation. There is only one sample: from students at the university. The census does not represent a separate population.