7: Confidence Intervals
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- 7.1: Confidence Intervals Concepts
- In this chapter, you will learn to construct and interpret confidence intervals. You will also learn a new distribution, the Student's-t, and how it is used with these intervals. Throughout the chapter, it is important to keep in mind that the confidence interval is a random variable. It is the population parameter that is fixed.
- 7.2: Confidence Interval for a Proportion
- The procedure to find the confidence interval, the sample size, the error bound, and the confidence level for a proportion is similar to that for the population mean, but the formulas are different.
- 7.3: Confidence Interval for a Mean
- We rarely know the population standard deviation. In the past, when the sample size was large, this did not present a problem to statisticians. They used the sample standard deviation ss as an estimate for σσ and proceeded as before to calculate a confidence interval with close enough results. However, statisticians ran into problems when the sample size was small. A small sample size caused inaccuracies in the confidence interval.
- 7.4: Confidence Interval for Standard Deviation
- This section discusses how to read the chi-squared distribution table and construct a confidence interval for population standard deviation.