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Inference comparing two groups or populations

AP Stats: DAT (BI), DAT‑3 (EU), UNC (BI), UNC‑4 (EU), VAR (BI), VAR‑6 (EU)

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)
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Confidence intervals for the difference between two proportions
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Examples identifying conditions for inference on two proportions
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Calculating a confidence interval for the difference of proportions
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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)
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Hypothesis test for difference in proportions
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Constructing hypotheses for two proportions
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Hypothesis test for difference in proportions example
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Comparing P value to significance level for test involving difference of proportions
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Confidence interval for hypothesis test for difference in proportions
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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!

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)
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Conditions for inference for difference of means
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Constructing t interval for difference of means
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Calculating confidence interval for difference of means
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Practice
Conditions for inference on two meansGet 3 of 4 questions to level up!
Two-sample t interval for the difference of meansGet 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)
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Hypotheses for a two-sample t test
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Example of hypotheses for paired and two-sample t tests
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Two-sample t test for difference of means
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Conclusion for a two-sample t test using a P-value
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Conclusion for a two-sample t test using a confidence interval
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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!

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.