# Inference comparing two groups or populations

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.

This course contains 4 segments:

**Confidence intervals for the difference between two proportions**

We can build a confidence interval to estimate the difference between two population proportions. For example, a politician might poll samples of people from two different locations to estimate the difference in the percent of voters that support their campaign.

**Testing the difference between two proportions**

We can do a significance test to judge if the difference between two proportions is significant (unlikely to occur by chance alone). For example, a company might want to test to see if there is a difference in what percent of their employees are satisfied between two of their locations.

**Confidence intervals for the difference between two means**

We can build a confidence interval to estimate the difference between two population means. For example, a food scientist might want to estimate the difference in the average sizes of two varieties of the same fruit.

**Testing the difference between two means**

We can do a significance test to judge if the difference between two means is significant (unlikely to occur by chance alone). For example, a chain of restaurants might want to test to see if there is a difference in the average portion size between two of their locations.

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Length | 4 segments |

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Cost | Free |

From | Khan Academy |

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Language | English |

Subjects | Mathematics |

Tags | Math |

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Rating | Not enough ratings |
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Length | 4 segments |

Starts | On Demand (Start anytime) |

Cost | Free |

From | Khan Academy |

Download Videos | On all desktop and mobile devices |

Language | English |

Subjects | Mathematics |

Tags | Math |

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