Hi,

So I take it you have ran a regression such as where is some unobservable error term, and obtained estimators for the coefficients(often called beta hat - , as well as the standard errors of the coefficents

The 95% confidence interval will be

Where is the t-stat value at the 2.5% level of significance for however many degrees of freedom in the regression. So if you had n=100 observations, and the model above with a constant and one explanatory variable you would have k=2, so you would need a t-stat of