In: Statistics and Probability
QUESTION 4 (2 + 1 + 2 + 1 + 4 =10 marks)
It is believed that cities tend to attract workers that are better educated. A sample of 610 people were classified by their highest education level (Primary and secondary school, Undergraduate and Postgraduate degree) and whether a person is working in a city or a town. The following information was obtained:
What is the probability that a person, who has completed primary and secondary school as their highest qualification, works in a town. Show your working.
Let the variable Education represent the highest education level and the variable Working Status represent whether a person is working in a city or a town. Name the dependent variable.
We would like to investigate if there is an association between the level of education and whether a person is working in a city or town. What type of test would you conduct and why?
State the appropriate hypotheses statements of the test above.
Assume that we carry out the test above at the 1% level of significance. The test statistic value is 4.75. State the decision rule, decision, and conclusion in the context of this question. (Hint: You can use a critical value approach OR p-value approach to derive your decision)
Answer:-
Given That:-
It is believed that cities tend to attract workers that are better educated. A sample of 610 people were classified by their highest education level (Primary and secondary school, Undergraduate and Postgraduate degree) and whether a person is working in a city or a town.
Given,
Does Work | Does not work | Total | |
Primary and secondary education | 51 | 38 | 89 |
Undergraduate degree | 220 | 129 | 349 |
Posrgraduate degree | 116 | 56 | 172 |
Total | 387 | 223 | 610 |
a) What is the probability that a person, who has completed primary and secondary school as their highest qualification, works in a town. Show your working.
Probability = 51/89 = 0.57
b) Let the variable Education represent the highest education level and the variable Working Status represent whether a person is working in a city or a town. Name the dependent variable.
The dependent variable is the working status.
c) We would like to investigate if there is an association between the level of education and whether a person is working in a city or town. What type of test would you conduct and why?
The chi-square test of association would be appropriate here because we have two categorical variables.
d) State the appropriate hypotheses statements of the test above.
The hypothesis being tested is:
H0: There is no association between the level of education and whether a person is working in a city or town.
Ha: There is an association between the level of education and whether a person is working in a city or town.
e) Assume that we carry out the test above at the 1% level of significance. The test statistic value is 4.75. State the decision rule, decision, and conclusion in the context of this question. (Hint: You can use a critical value approach OR p-value approach to derive your decision)
Decision rule:
Reject H0 if the p-value < 0.01.
Does Work | Does not work | Total | |
Primary and secondary education Observed Expected O - E |
51 56.46 -5.46 0.53 |
38 32.54 5.46 0.92 |
89 89.00 0.00 1.45 |
Undergraduate degree Observed
Expected O - E |
220 221.41 -1.41 0.01 |
129 127.59 1.41 0.02 |
349 349.00 0.00 0.02 |
Posrgraduate degree Observed
Expected O - E |
116 109.12 6.88 0.43 |
56 62.88 -6.88 0.75 |
172 172.00 0.00 1.19 |
Total Observed
Expected O - E |
387 387.00 0.00 0.97 |
223 223.00 0.00 1.69 |
610 610.00 0.00 4.75 |
4.75 2 .2649 |
chi-square df p - value |
The p-value is 0.2649.
Since the p-value (0.2649) is greater than the significance level (0.01), we fail to reject the null hypothesis.
Therefore, we cannot conclude that there is an association between the level of education and whether a person is working in a city or town.
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