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