In: Statistics and Probability
The data below show sport preference and age of participant from a random sample of members of a sports club. Is there evidence to suggest that they are related?
Tennis | Swimming | Basketball | |
---|---|---|---|
18-25 | 88 | 94 | 74 |
26-30 | 107 | 84 | 91 |
31-40 | 79 | 62 | 55 |
Over 40 | 76 | 71 | 43 |
What can be concluded at the α = 0.10 significance level?
The Observed and expected values are given below. Each Expected value = Row Total * Column Total / N
Observed | ||||
Tennis | Swimming | Basketball | Total | |
18-25 | 88 | 94 | 74 | 256 |
26-30 | 107 | 84 | 91 | 282 |
31-40 | 79 | 62 | 55 | 196 |
Over 40 | 76 | 71 | 43 | 190 |
Total | 350 | 311 | 263 | 924 |
Expected | ||||
Tennis | Swimming | Basketball | Total | |
18-25 | 96.97 | 86.16 | 72.87 | 256 |
26-30 | 106.82 | 94.92 | 80.27 | 282 |
31-40 | 74.24 | 65.97 | 55.79 | 196 |
Over 40 | 71.97 | 63.95 | 54.08 | 190 |
Total | 350 | 311 | 263 | 924 |
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The correct test to be used is : Test of Independence
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The Hypothesis:
Option 1: H0: Age and sport preference are independent.
Option 3: H1: Age and sport preference are dependent.
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The Test Statistic
# | Observed | Expected | (O-E) | (O-E)2 | (O-E)2/E |
1 | 88 | 96.97 | 8.969697 | 80.45546 | 0.829697 |
2 | 107 | 106.82 | -0.18182 | 0.033058 | 0.000309 |
3 | 79 | 74.24 | -4.75758 | 22.63453 | 0.304873 |
4 | 76 | 71.97 | -4.0303 | 16.24334 | 0.225697 |
5 | 94 | 86.16 | -7.8355 | 61.39503 | 0.712533 |
6 | 84 | 94.92 | 10.91558 | 119.15 | 1.255326 |
7 | 62 | 65.97 | 3.969697 | 15.75849 | 0.238875 |
8 | 71 | 63.95 | -7.04978 | 49.69945 | 0.777158 |
9 | 74 | 72.87 | -1.1342 | 1.286408 | 0.017654 |
10 | 91 | 80.27 | -10.7338 | 115.2137 | 1.435395 |
11 | 55 | 55.79 | 0.787879 | 0.620753 | 0.011127 |
12 | 43 | 54.08 | 11.08009 | 122.7683 | 2.270121 |
Total | 8.079 |
test = 8.08
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The p value: For (8.08, 6) = 0.2323
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The p value is greater than (0.10)
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Based on this we should: Option 2: Fail to reject the Null.
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The Conclusion: Option 2: There is insufficient evidence to conclude that age and sports are dependent.
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