## 5.1 Introduction to Confidence Intervals

An introduction to confidence intervals.

## 5.2 Deriving a Confidence Interval for the Mean

I derive the appropriate formula for a confidence interval for the population mean mu, when sampling from a normally distributed population with a known value of sigma. (The purpose of this video is to show the rationale behind the confidence … Watch the Video

## 5.3 Intro to Confidence Intervals for One Mean (Sigma Known)

An introduction to confidence intervals for the population mean mu. These methods are appropriate when we are sampling from a normally distributed population, where the population standard deviation sigma is known. When the population standard deviation is not known, as … Watch the Video

## 5.4 Finding the Appropriate z Value for the Confidence Interval Formula

I show how to find the appropriate z value (using the standard normal table) when calculating a confidence interval.

## 5.5 Confidence Intervals for One Mean: Interpreting the Interval

Interpreting a confidence interval for the population mean mu. Some reasonable interpretations are discussed, as are some common misconceptions. Many of these concepts hold for confidence intervals for other parameters.

## 5.6 What Factors Affect the Margin of Error?

A look at the effect of various factors (the standard deviation, the sample size, and the confidence level) on the margin of error of a confidence interval for the population mean.

## 5.7 Confidence Intervals for One Mean: Sigma Not Known (t Method)

Intro to confidence intervals for mu based on the t distribution. These methods are appropriate when we are sampling from a normally distributed population and the population standard deviation (sigma) is not known.

## 5.8 Intro to the t Distribution (non-technical)

A brief non-technical introduction to the t distribution, and how it relates to the standard normal distribution.

## 5.9 Confidence Intervals for One Mean: Determining the Required Sample Size

I find the sample size required to obtain a given margin of error in a confidence interval for mu. I discuss the appropriate formula and work through an example.

## 5.10 Confidence Intervals for One Mean: Investigating the Normality Assumption

A discussion of the assumptions when using the t procedure to construct a confidence interval for the population mean mu. The assumptions are discussed, and the effect of different violations of the normality assumption is investigated through simulation.