Hello,

The below image shows a regression output and the confidence intervals for the coefficients:

In the above part I have a question:

Why do we use the t-statistic to find out the significance of the predictors while we use the z-statistic to compute the confidence interval of the predictor coefficients?

Is it because t-statistic is for the sample of data whose population variance is not known and the z-statistic because we are estimating population parameters??

Can someone please help me on this??