In: Statistics and Probability
The president of a company asked a random sample of employees how they felt about the work they were doing. The following table gives a breakdown of their responses by gender. Does the data provide enough evidence to conclude that the level of job satisfaction is related to gender? Use alpha = .10
Gender |
Very Interesting |
Fairly Interesting |
Not Interesting |
Male |
70 |
41 |
9 |
Female |
35 |
34 |
11 |
The null hypothesis
Solution:
Here, we have to use chi square test for independence of two categorical variables.
Null hypothesis: H0: The level of job satisfaction is not related to gender.
Alternative hypothesis: Ha: The level of job satisfaction is related to gender.
We are given level of significance = α = 0.10
Test statistic formula is given as below:
Chi square = ∑[(O – E)^2/E]
Where, O is observed frequencies and E is expected frequencies.
E = row total * column total / Grand total
We are given
Number of rows = r = 2
Number of columns = c = 3
Degrees of freedom = df = (r – 1)*(c – 1) = 1*2 = 2
α = 0.10
Critical value = 4.60517
(by using Chi square table or excel)
Calculation tables for test statistic are given as below:
Observed Frequencies |
||||
Level of job Satisfaction |
||||
Gender |
C1 |
C2 |
C3 |
Total |
Male |
70 |
41 |
9 |
120 |
Female |
35 |
34 |
11 |
80 |
Total |
105 |
75 |
20 |
200 |
Expected Frequencies |
||||
Level of job Satisfaction |
||||
Gender |
C1 |
C2 |
C3 |
Total |
Male |
63 |
45 |
12 |
120 |
Female |
42 |
30 |
8 |
80 |
Total |
105 |
75 |
20 |
200 |
Calculations |
||
(O - E) |
||
7 |
-4 |
-3 |
-7 |
4 |
3 |
(O - E)^2/E |
||
0.777778 |
0.355556 |
0.75 |
1.166667 |
0.533333 |
1.125 |
Chi square = ∑[(O – E)^2/E] = 4.708333
P-value = 0.094973
(By using Chi square table or excel)
P-value < α = 0.10
So, we reject the null hypothesis
There is sufficient evidence to conclude that the level of job satisfaction is related to gender.
Answer:
The null hypothesis