# Week 6 - Confidence Intervals

**Confidence Intervals**

**Why**

Recall that one of our original goals was to use a sample mean to estimate a population mean. We will now formulate the error for this estimation and we can then make scientific arguments regarding the range of values that a population mean can take on. This will show how the sample size, spread, and confidence of an estimate all play an important role in estimation. Finally you will know enough to validate the statistical claims made by others about population means. The process will also be applied to proportions but the theory behind these estimates will not be developed.

**Learning Objectives**

- Know how to determine and interpret a confidence interval for the mean
- Know how to determine and interpret a confidence interval for the proportion
- Understand the roles of sample size, confidence level, and spread on the margin of error.

**Performance Criteria**

- The learner will calculate confidence intervals using technology accurate to 2 decimal places.
- The learner will interpret confidence intervals using a complete sentence that includes the units of the random variable and the confidence level.

***NEW*** Click on "Textbook" to view the assigned reading or read Sections 8.1-8.3 from your print or digital copy.

The version of chapter 8 is annotated with notes and images from me. Use this instead of the web book.

**Videos**

Chapter 8 This is a video by Gary Parker covering chapter 8

Confidence Intervals for Means with StatKey

Confidence Intervals for Proportions with Statkey

**Plan**

- Review - Read the above components and post any questions in the forum below.
- Practice - Complete the practice exercises that follow.
- Think - Answer the Critical Thinking questions in the "Critical Thinking" forum.
- Apply - Complete the Application Problems and upload your completed file
- Assess - Complete the Self Assessment for this week's experience.

If you have any questions about the content (readings, problems, etc.) then post in the "Questions about week 6" forum.

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