If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

To log in and use all the features of Khan Academy, please enable JavaScript in your browser.

Main content

Unit: Inference comparing two groups or populations

AP Stats:

DAT (BI)

,

DAT‑3 (EU)

,

UNC (BI)

,

UNC‑4 (EU)

,

VAR (BI)

,

VAR‑6 (EU)

,

VAR‑7 (EU)

0

Possible mastery points

Confidence intervals for the difference between two proportions

AP Stats:

UNC (BI)

,

UNC‑4 (EU)

,

UNC‑4.I (LO)

,

UNC‑4.I.1 (EK)

,

UNC‑4.J (LO)

,

UNC‑4.J.1 (EK)

,

UNC‑4.K (LO)

,

UNC‑4.K.1 (EK)

Learn

Confidence intervals for the difference between two proportions

(Opens a modal)

Examples identifying conditions for inference on two proportions

(Opens a modal)

Calculating a confidence interval for the difference of proportions

(Opens a modal)

Practice

Conditions for inference on two proportionsGet 3 of 4 questions to level up!

Two-sample z interval for the difference of proportionsGet 3 of 4 questions to level up!

Testing the difference between two proportions

AP Stats:

DAT (BI)

,

DAT‑3 (EU)

,

DAT‑3.C (LO)

,

DAT‑3.C.1 (EK)

,

DAT‑3.D (LO)

,

DAT‑3.D.1 (EK)

,

DAT‑3.D.2 (EK)

,

UNC (BI)

,

UNC‑4 (EU)

,

UNC‑4.N (LO)

,

UNC‑4.N.1 (EK)

,

VAR (BI)

,

VAR‑6 (EU)

,

VAR‑6.H (LO)

,

VAR‑6.H.1 (EK)

,

VAR‑6.H.2 (EK)

,

VAR‑6.H.3 (EK)

,

VAR‑6.I (LO)

,

VAR‑6.I.1 (EK)

,

VAR‑6.J (LO)

,

VAR‑6.J.1 (EK)

,

VAR‑6.K (LO)

,

VAR‑6.K.1 (EK)

Learn

Hypothesis test for difference in proportions

(Opens a modal)

Constructing hypotheses for two proportions

(Opens a modal)

Hypothesis test for difference in proportions example

(Opens a modal)

Comparing P value to significance level for test involving difference of proportions

(Opens a modal)

Confidence interval for hypothesis test for difference in proportions

(Opens a modal)

Practice

Writing hypotheses for testing the difference of proportionsGet 3 of 4 questions to level up!

Test statistic in a two-sample z test for the difference of proportionsGet 3 of 4 questions to level up!

P-value in a two-sample z test for the difference of proportionsGet 3 of 4 questions to level up!

Making conclusions about the difference of proportionsGet 3 of 4 questions to level up!

Quiz 1

Level up on the above skills and collect up to 600 Mastery points

Confidence intervals for the difference between two means

AP Stats:

UNC (BI)

,

UNC‑4 (EU)

,

UNC‑4.V (LO)

,

UNC‑4.V.1 (EK)

,

UNC‑4.V.2 (EK)

,

UNC‑4.W (LO)

,

UNC‑4.W.1 (EK)

,

UNC‑4.X (LO)

,

UNC‑4.X.1 (EK)

,

UNC‑4.X.2 (EK)

,

UNC‑4.Y (LO)

,

UNC‑4.Y.1 (EK)

,

UNC‑4.Y.2 (EK)

Learn

Conditions for inference for difference of means

(Opens a modal)

Constructing t interval for difference of means

(Opens a modal)

Calculating confidence interval for difference of means

(Opens a modal)

Practice

Conditions for inference on two meansGet 3 of 4 questions to level up!

Two-sample t interval for the difference of means (calculator-active)Get 3 of 4 questions to level up!

Testing the difference between two means

AP Stats:

DAT (BI)

,

DAT‑3 (EU)

,

DAT‑3.H (LO)

,

DAT‑3.H.1 (EK)

,

DAT‑3.H.2 (EK)

,

UNC (BI)

,

UNC‑4 (EU)

,

UNC‑4.AA (LO)

,

UNC‑4.AA.1 (LO)

,

VAR (BI)

,

VAR‑7 (EU)

,

VAR‑7.B (LO)

,

VAR‑7.B.2 (EK)

,

VAR‑7.C (LO)

,

VAR‑7.C.2 (EK)

,

VAR‑7.F (LO)

,

VAR‑7.F.1 (EK)

,

VAR‑7.G (LO)

,

VAR‑7.G.1 (EK)

,

VAR‑7.I (LO)

,

VAR‑7.I.1 (EK)

Learn

Hypotheses for a two-sample t test

(Opens a modal)

Example of hypotheses for paired and two-sample t tests

(Opens a modal)

Two-sample t test for difference of means

(Opens a modal)

Conclusion for a two-sample t test using a P-value

(Opens a modal)

Conclusion for a two-sample t test using a confidence interval

(Opens a modal)

Practice

Writing hypotheses to test the difference of meansGet 3 of 4 questions to level up!

Test statistic in a two-sample t testGet 3 of 4 questions to level up!

P-value in a two-sample t testGet 3 of 4 questions to level up!

Making conclusions about the difference of meansGet 3 of 4 questions to level up!

Quiz 2

Level up on the above skills and collect up to 600 Mastery points

Up next for you:

Unit test

Level up on all the skills in this unit and collect up to 1200 Mastery points!

About this unit

If a poll from one location shows 55% of voters support a measure, but a poll from another location shows 45% support, does that mean there is a difference between the two populations? We can make a confidence interval to estimate the difference, or do a significance test to see if the difference is significant. We'll use similar methods to compare the means of two groups.

AP® is a registered trademark of the College Board, which has not reviewed this resource.