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
(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

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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!

Confidence intervals for the difference between two means

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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 meansGet 3 of 4 questions to level up!

Testing the difference between two means

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!

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.