In: Statistics and Probability
A comparative study of job satisfaction was conducted in
factories from different regions of the country. As part of the
study, samples of workers from two factories were taken,
One in the north and the other in the south, and the employees were
asked how satisfied they were with the work. Here are the
results:
Region | Amount not Satisfied | Amount Satisfied | Amount very satisfied |
Northern (X) | 5 | 20 | 45 |
Southern (Y) | 35 | 15 | 10 |
1) Does the location of the factory affect the satisfaction level? Test with significance level=3%.
2) Is the degree of satisfaction uniform? Does each level of satisfaction have a 1/3 chance of happening? Check if this is the case.
1)
Ho: location of the factory does not affect the satisfaction level
Ha: location of the factory affect the satisfaction level
Chi-Square Test of independence | |||||||
Observed Frequencies | |||||||
0 | |||||||
0 | not | satistified | very satisfied | Total | |||
X | 5 | 20 | 45 | 70 | |||
Y | 35 | 15 | 10 | 60 | |||
Total | 40 | 35 | 55 | 130 | |||
Expected frequency of a cell = sum of row*sum of column / total sum | |||||||
Expected Frequencies | |||||||
not | satistified | very satisfied | Total | ||||
X | 40*70/130=21.538 | 35*70/130=18.846 | 55*70/130=29.615 | 70 | |||
Y | 40*60/130=18.462 | 35*60/130=16.154 | 55*60/130=25.385 | 60 | |||
Total | 40 | 35 | 55 | 130 | |||
(fo-fe)^2/fe | |||||||
X | 12.6992 | 0.0706 | 7.992 | ||||
Y | 14.8157 | 0.0824 | 9.324 |
Chi-Square Test Statistic,χ² = Σ(fo-fe)^2/fe =
44.9840
Level of Significance = 0.03
Number of Rows = 2
Number of Columns = 3
Degrees of Freedom=(#row - 1)(#column -1) = (2- 1 ) * ( 3- 1 )
= 2
p-Value = 0.0000 [Excel function:
=CHISQ.DIST.RT(χ²,df) ]
Decision: p-value < α , Reject
Ho
there is enough evidence that location of the factory affect the satisfaction level
2)
observed frequencey, O | expected proportion | expected frequency,E | (O-E) | (O-E)²/E | |
40 | 0.333 | 43.33 | -3.33 | 0.256 | |
35 | 0.333 | 43.33 | -8.33 | 1.603 | |
55 | 0.333 | 43.33 | 11.67 | 3.141 |
chi square test statistic,X² = Σ(O-E)²/E =
5.000
level of significance, α= 0.03
Degree of freedom=k-1= 3 -
1 = 2
P value = 0.0821 [ excel function:
=chisq.dist.rt(test-stat,df) ]
Decision: P value >α , Do not reject Ho
there is no enough evidence to reject the claim that degree of satisfaction is uniform