Dear Stataforum,

I am currently investigating the Norwegian electricity market.

I am running two regressions using -xtivreg-.

Regression 1: y = a + b1x1 + b2x2 + u
Regression 2: y = a + d1x1 + d2x2 + u

I use the same dependent variable and independent variables in both equation. The difference between the two is the number of firms.

Is there any way to test whether b1 and d1 are statistical different?

I will be grateful for any insight and help you can provide.

Best regards,
Mats