Today we are going to make an 80% confidence interval for the average weight of a 4 year old. So we will know whether it will ruin your back to have one hold on like a monkey. So, we have an average X- bar, which is 40lbs. Notice, sigma is Continue Reading

# interval

## Calculating the Confidence interval for a mean using a formula – statistics help

Calculating a confidence interval for a mean using a formula. To find out about confidence intervals, watch our video “Understanding Confidence Intervals.” This video introduces the traditional way to find a confidence interval for a mean using a formula. Usually we just get the computer to calculate the confidence interval Continue Reading

## Finding the Appropriate z Value for the Confidence Interval Formula (Using a Table)

Let’s look at finding the appropriate z value using the standard normal table when constructing a confidence interval. Suppose we wish to use this confidence interval formula to obtain a (1-alpha) times 100% confidence interval for mu. This would be the appropriate formula if we were sampling from a normally Continue Reading

## StatCrunch: Computing Confidence Intervals for a Mean with Raw Data

In this video you will learn to compute one sample t confidence intervals with raw data using StatCrunch. The dataset I’m using is called “apple juice bottles”. This dataset comes from Statistics: Informed Decisions Using Data by Michael Sullivan. The “apple juice” column contains the amount in ounces it each Continue Reading

## Understanding and calculating confidence intervals for population proportions – statistics help

Understanding and calculating confidence intervals for proportions. Hi I’m Dr Nic from Creative Maths including Statistics Learning Centre. In this video I’m going to explain what confidence intervals for proportions tell us, how to calculate them, what the effect of different confidence levels is, and some important things to remember Continue Reading

## Linear Regression t test and Confidence Interval

BAM! Mr. Tarrou. In this video we are going to be talking about inference for regression. Specifically linear regression t tests and confidence intervals about the slope of the regression line. Is there a linear relationship between two variables? Well, if the slope of the regression line equals zero then Continue Reading

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

Let’s look into confidence intervals for the population mean mu using the t procedure. I am going to assume that you’ve already been introduced to the notion of confidence intervals for the population mean. And I look at that introduction in other videos. For the methods used in this video Continue Reading

## Confidence Intervals for One Mean: Interpreting the Interval

Let’s look at properly interpreting a confidence interval for the population mean mu. The population mean mu is a parameter. It has a fixed value that is usually unknown. And we often wish to estimate mu with a confidence interval. Suppose we use this confidence interval formula to obtain a Continue Reading

## Deriving a Confidence Interval for the Mean (The Rationale Behind the Confidence Interval Formula)

Let’s take a look at deriving a confidence interval for the population mean mu, when sampling from a normally distributed population with a known value of the population standard deviation sigma In this video I’m going to derive the appropriate confidence interval formula, and I work through an example in Continue Reading

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

Let’s look at confidence intervals for the population mean mu. The methods used in this video will be appropriate when we are sampling from a normally distributed population with a known value of the population standard deviation sigma. The sample mean X bar is a point estimator of the population Continue Reading