Respuesta :

diamond03
mean = (21+6+18+21+20+14+19)/7 = 17 

take sum of squares and fine their mean = 2199/7 = 314.1428 

S.d =(314.1428-(17)^2)^(1/2) 

= 5.01
Sora0115
If I did do my math correctly, then it should be none of the above, however, I checked it with a standard deviation  calculator and you are wrong. Try the formula again.