function_nbr:determines which function to use according to the following table: \t1 AVERAGE \t2 COUNT \t3 COUNTA \t4 MAX \t5 MIN \t6 PRODUCT \t7 STDEV \t8 STDEVP \t9 SUM \t10 VAR \t11 VARP
funtzio_zenb: taula honen arabera zer funtzio erabili zehazten du: \t1 AVERAGE \t2 COUNT \t3 COUNTA \t4 MAX \t5 MIN \t6 PRODUCT \t7 STDEV \t8 STDEVP \t9 SUM \t10 VAR \t11 VARP