Free Statistics Help Book
An Interactive Multimedia introductory-level statistics book.
The book features interactive demos, simulations and case studies.
Chapter
Section
Normal Distributions :  

Varieties of Normal Distribution Demo



Questions to be answered before the simulation are not yet implemented in this test version.


Begin by answering the questions, even if you have to guess. The first time you answer the questions you will not be told whether you are correct or not.


Once you have answered all the questions, answer them again using the simulation to help you. This time you will get feedback about each individual answer.


General Instructions


This demonstration allows you to change the mean and standard deviation of two normal distributions and observe the effects on the shapes of the distributions.When the demonstration begins, the red distribution has a mean of 50 and a standard deviaton of 10. The blue distribution has a mean of 50 and a standard deviation of 5. Notice how much more spread out the red distribution is than the blue distribution.


Choose different values for the two distributions and investigate their effects.


Step by Step Instructions


Change the mean of the blue distribution to 60 and notice what happens. Did its shape change, or just its position along the X-axis?


Compare the blue and red distributions. Do the areas under the curve appear to differ? They should be the same: the red distribution is wider but not as high as the blue distribution.


Experiment by changing the means and standard deviations of both distributions to explore the variety of shapes a normal distribution can take on. Note that some values will not allow the distributions to be displayed in full.


Summary


Normal distributions have different means and standard deviations. Normal distributions that differ only in their means have the same shape. Normal distributions with different standard deviations are more or less spread out.


Copyright 2011