11.2. Hypothesis Test: Multinomial Population

 

General Case:

Suppose there are K populations. We want to test

 

vs.

where 

We also have the following information:

total sample size:

observed numbers: .

In addition, as  is true, the expected numbers are

expected numbers:

 

Chi-Square Test:

The chi-square test with level of significance  for

 

vs

is to

,

where

,

 can be obtained by ,

and where  is the random variable distributed as chi-square distribution with degrees of  

In addition, .

 

Example 2:

The following data are the frequencies of products of throwing a dice 120 times:

Point

1

2

3

4

5

6

Frequency

13

24

18

22

19

24

Please test if the dice is fair (i.e., ) with .

[solution:]

Then,

Since 

,

we do not reject .

 

JavaStatSoft:

Chi-square test:

Statistics -> Tests -> Chi-Square Tests -> Hypothesis Test: Multinomial Population