Part Number
Issue
Date
Page
6159937790
12
03/2018
136 / 184
03/2018
136 (184)
3) Calculation of W:
2
2
S
b
W
Could be a 5% probability that there is not a normal distribution if W is lower than W95 given in
the following table:
N
W95
15
0.881
20
0.905
25
0.918
30
0.927
35
0.934
40
0.940
45
0.945
50
0.947
9.2.5
Normal Distribution Test: Population under 50 measurements
(Chi-Squared test)
1) Distribute into classes of at least 4 or 5 measurements
2) Calculate the mean and standard deviation mean:
N
x
x
N
i
i
1
Standard deviation:
1
1
2
N
x
x
N
i
i
3) Calculate for each class limit l
i
:
x
l
u
i
i