Hi everybody! - I m writing an essay using the Excel multiple linear regression.This essay is kind of formal and i have to write down the multiple linear regression's equations that i used..My problem is that i cant find the equations or the method that Excel actually uses for multiple linear regression.The Excel "help" and some relevant web pages just refer to the equations of simple linear regression of 2(X and Y) variables and least squares..And those which refer to multiple regression are giving some general tips and information but none makes 100% clear the method or the equations that Excel actually uses for multiple linear regression and coefficients caculation.... I know the basic method for multiple regression using data matrixes giving the coefficients (Y=Xb+E---> b=( X'X)(-1)(X'Y) etc.) but i cant tell if Excel is using it with no differences,correlations etc.Can you help me please?Anything......
-My final regression functions giving the Y values, have 5 or 6 (X) different variables with 23 observations for each variable.My data are strongly linear with determination (R Square) over 0,95.However the t-Student values( for 95% precision) for the variables' coefficents are below the crtical "Student" value in many cases.I would like most of the X variables to be statistically important in my Y functions.I know it is impossible that all the X variables are statistically important (with t-Student) but i would like them to be as more as possible...I tried to improve that so I have tried to make some combinations among the X variables different from those i originally wanted to..i tried to increase the variables' observations with some more data ...i transformed my data to logarithms and i tested regression again but it didnt help much.Any ideas or tips for how i can do it?Even a new data process method is acceptable! Thanks for your help!Cheers! . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
