1. Exercice 17
xi xi 2 (xi − x)2
1 1 4
2 4 1
3 9 0
4 16 1
5 25 4
(a) Moments simples d’ordre 1 et 2
xi 15
m1 = x = = =3
N 5
xi 2 55
m2 = = = 11
N 5
(xi − x)2 10
µ2 = = =2
N 5

2. Exercice 17 (suite..)
(b) On vérifie la relation :
µ2 = m2 − m1 2
= 11 − 32
=2