Last year labour union agents listed five categories and asked a number of employees to mark the one most important to her/him. The categories and corresponding percentages of favourable responses are listed in table 1. A new survey has been performed, and the agents need to determine whether the current distribution of responses deviates from the previous year. The results of this new survey are listed in table 2. Establish two working hypotheses, namely null-hypothesis, , and alternative hypothesis, . Use a Chi-square distribution to test the goodness-of-fit between the sample statistics Account for the degrees of freedom Using the degrees of freedom estimate a critical value for testing the sample statistics at a 99% confidence level (1% level of significance) Conclude the test and interpret the conclusion Table 1. Categories in a union survey Category Percentage of Favourable Responses Vacation time 4% Salary 65% Safety regulations 13% Health and retirement benefits 12% Overtime policy and pay 6% Table 2. Survey responses new survey Category Observed Favourable Responses Vacation time 30 Salary 290 Safety regulations 70 Health and retirement benefits 70 Overtime policy and pay 40 Values of the Chi-square test, df = degrees of freedom
Last year labour union agents listed five categories and asked a number of employees to mark the one most important to her/him. The categories and corresponding percentages of favourable responses are listed in table 1. A new survey has been performed, and the agents need to determine whether the current distribution of responses deviates from the previous year. The results of this new survey are listed in table 2.
- Establish two working hypotheses, namely null-hypothesis, , and alternative hypothesis, .
- Use a Chi-square distribution to test the goodness-of-fit between the sample statistics
- Account for the degrees of freedom
- Using the degrees of freedom estimate a critical value for testing the sample statistics at a 99% confidence level (1% level of significance)
- Conclude the test and interpret the conclusion
Table 1. Categories in a union survey
Category |
Percentage of Favourable Responses |
Vacation time |
4% |
Salary |
65% |
Safety regulations |
13% |
Health and retirement benefits |
12% |
Overtime policy and pay |
6% |
Table 2. Survey responses new survey
Category |
Observed Favourable Responses |
Vacation time |
30 |
Salary |
290 |
Safety regulations |
70 |
Health and retirement benefits |
70 |
Overtime policy and pay |
40 |
Values of the Chi-square test, df = degrees of freedom
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