HOW TO PERFORM QUERIES TO CALCULATE REGR_SXX, REGR_SYY,REGR_SXY? What are their queries in Wolfram?
Help > Wolfram Documentation regression
First hit is quite useful, probably others are as well.
Generally one should check documentation before asking in a forum. And questions should be comprehensible without requiring recourse to an internet search for commands from unspecified other languages or programs.