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Inference comparing two groups or populations

Confidence intervals for the difference between two proportions

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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

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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

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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

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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.