How does Stata calculate T-Values?

[Rik Vinke]

Dear all,

I'm very curious as to how Stata exactly calculates T-Values.

For example: when I do

ttest car == 0 (where car is cumulative abnormal returns)

this is the output:

mean = mean(car) t = 3.4898
Ho: mean = 0 degrees of freedom = 5485

So how does Stata compute t? By what formula?

[William Lisowski]

This is documented in the Methods and Formulas section of the ttest documentation, which you will find the the Stata Base Reference Manual PDF included in the Stata installation (since version 11) and accessible from within Stata - for example, through Stata's Help menu.

[Rik Vinke]

Thank you very much!