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"Comparing Normal and T-distributions" icon

Comparing Normal and T-distributions

Module overlays the t-distribution on top of the normal distribution showing convergence as the degrees of freedom increases.  Z scores and T-scores for alpha/2 tail probabilities are calculated and plotted for both the normal distribution and the t-distribution allowing students to visually understand the difference in confidence interval size when using the normal or the t-distribution as well as convergence between the two for larger sample sizes.  User specifies degrees of freedom, alpha/2 tail probabilities, and the plot range.  Ordinate scale and plot values are automatically scaled and calculated on the fly in accordance with user specified inputs. 

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Tiantian Qin
Tiantian Qin (Faculty)
8 years ago
This model shows normal and t distribution in the same plot. As clear as the difference between the two distritbuion is on the plot, one might wonder what other application this module has. In fact, an instructor can just draw the density curve on board to demonstrate the difference, which is much easier than setting up the module in class.

Technical Remarks:

In order to see the plot, one has to specify the max and mix boundary in the x scale, or no plot is shown. There should be some default values such as -4 or 4 to avoid the problem.