@Carl Love Hello Carl,
Above, I have just given a copy of the 80 datas extracted from my excel sheet. Obviously, I define a matrix in Maple when I imported the datas with instruction : Mat2 := ExcelTools:-Import("filetest.xlsx", "Somme", "G2:G81") .
Concerning the precision of the result, I have calculated all the (ai) coefficients with the Shapiro-Wilks matrix formulas, in order to estimate W then the p-value. I verified also my result of W with the square of the correlation coefficient between the ai coef and the xi datas. It is OK. (the total calculous takes only a few seconds with EXCEL).
I confirm that the caculous from Maple doesn't seem to be right.
I am going to test your 2 ligns. I will inform you.
Thank you very much for help.