Normal distributions are good models for the randomness in many situations and are the basis for many statistical methods. In this sequence of videos, we’ll examine the properties of normal distributions and how to assess whether a set of data appear to be a sample of measurements from a normal distribution.
Normal Distributions
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Notes on the video: Normal Distributions
For the derivation of the expectation and variance for two results quoted near the end of this video, see these notes for some mathematical details.
Using a Normal Probability Table
A normal probability table can be used to find probabilities and quantiles for values from the standard normal distribution. In this video, we demonstrate how to use a table. The particular normal probability table used in the video is from OpenIntro Statistics (external link, opens in new window) (licensed under the Creative Commons BY-SA 3.0 license).
Stream the video without the embedded quiz questions by clicking on the video link below. Closed captions are available.
Notes on the video: Using a Normal Probability Table
In practice, statistical software is typically used to obtain probabilities and quantiles from normal distributions. The Probability Distribution Calculator is an app that can be used for this.
A Normal Distribution Problem
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Notes on the video: A Normal Distribution Problem
Normal Quantile Plots
Normal quantile plots (sometimes called Q-Q plots because they plot quantiles from data versus the corresponding quantiles from a normal distribution) are useful graphical displays to assess whether a set of data appear to be a sample of measurements from a normal distribution.
Stream the video without the embedded quiz questions by clicking on the video link below. Closed captions are available.
Notes on the video: Normal Quantile Plots