When is a 2 sample t-test equals the regression slope t-test?

[Mor Zahavi]

This is pretty basic:

Say I want to produce a paired sample t-test of 2 variables V1 and V2. What would be the Stata regression command that will give me the same value of the t-test statistic for the slope being zero?

MWE:

sysuse auto, clear
ttest price == mpg

In this example the t-test is 17.9, so I am looking for the regression command of these 2 variables which produces t-statistic for the slope that is equal to 17.9.

(I thought it would be regress mpg price, noconstant but its not)

[Rich Goldstein]

I'm not sure I completely understand, but a paired t-test is the same as estimating a regression where the output variable is equal to the difference of the two variables and there are no predictors, but a constant is included:

sysuse auto
gen diff=price- mpg
regress diff

[Mor Zahavi]

That's exactly what I meant. Thanks.