10 DATA 10,20,20,50,30,60,40,90,50,100,60,130
20 mx = 0: my = 0: mxy = 0
30 FOR n = 1 TO 6
40 READ x, y
50 mx = mx + x: my = my + y: mxy = mxy + x * y
60 NEXT n
70 mx = mx / 6: my = my / 6: mxy = mxy / 6
80 PRINT "Covarian‡a="; mxy - mx * my