Purpose: The purpose of this program is to display a t-distribution and a standard normal distribution for the number of degrees of freedom specified by the user.
Download: You can download this program from within Stata by typing search tdemo (see How can I used the search command to search for programs and get additional help? for more information about using search).
Use of program: To use this program, type tdemo in the Stata command window. This opens a Stata graph window showing a t-distribution with one degree of freedom in red and a normal distribution in blue. If a number is typed after the tdemo command, a t-distribution with that number of degrees of freedom will be displayed.
Examples: The following shows the output from issuing the tdemo command with degrees of freedom value of 5.
. tdemo 5
The following shows the output from issuing the tdemo command with a degrees of freedom value of 5 and 1-tail rejection region.
. tdemo 5 1
The next example shows the output from issuing the tdemo command with a degrees of freedom of 5, a 1-tail rejection region wit alpha at .01.
. tdemo 5 2 .01