Main Concepts: The Normal Distribution |
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Main Concepts | Demonstration | Activity | Teaching Tips | Data Collection & Analysis | Practice Questions | Milestone | Fathom Tutorial | ||

Main Concepts Everybody believes in the normal approximation, the experimenters because they think it is a mathematical theorem,the mathematicians because |
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•The normal distribution is a mathematical model that idealizes distributions of variables that are symmetric and unimodal. However, keep in mind that there are other distributions that can model symmetric and unimodal distributions. • The normal distribution is merely one of many distributions,
all of which are used as idealized summaries of distributions in
populations. The area • The standard unit is a useful and fundamental way of
comparing observations from two different populations. In essence, we
use the standard • Empirical Rule: 95% of the data are within two standard
deviations of the mean in a normal curve. 68% are within one standard
deviation. 99.7% • Fewer populations than you may think or your book may
suggest actually have distributions that are well approximated by the
normal ## Tie-in to ProbabilityWe're currently
using the normal curve as a descriptive summary of a set of data or of
a population. For example, by "Normality is a myth; there never has, and never will be, a normal distribution", Geary, R.C. in Biometrika, "Testing for Normality", Volume 34, 1947 (p. 241) |