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; MODEL4.PRO          ; The name of this program, should I forget it.
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X=[7.,-9.,6.,4.] & Y=[-1.,3.,8.,15]      ; Arbitrary samples X and Y
N=N_ELEMENTS(X)                          ; n
MX=MEAN(X) & SX=STDEV(X)                 ; Mean and standard dev. of X
MY=MEAN(Y) & SY=STDEV(Y)                 ; Mean and standard dev. of Y
R1=TOTAL((X-MX)*(Y-MY))/((N-1.D0)*SX*SY) ; Linear corr. coeff. r
; -The same result could by obtained with the following IDl-command
R2=CORRELATE(X,Y)                        ; Linear coff. coeff. r 
PRINT,'R1= ',R1,', R2=',R2               ; Just checking           
Q=1.D0-erf(ABS(R1)*SQRT(N/2.D0))         ; Probability P(r>r1)
; -There is also most probably an IDL-routine for this purpose, but...
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END
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