chi-square_test
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I do not know exactly why the degree of freedom is important in a conceptual way -- so, having a difficulty explaining it. But, the idea behind it is that if you know totals of column and row, and the values of two cells (as a minimum requirement; | I do not know exactly why the degree of freedom is important in a conceptual way -- so, having a difficulty explaining it. But, the idea behind it is that if you know totals of column and row, and the values of two cells (as a minimum requirement; | ||
- | {{07-419434-a-tshirt-camp-scils-rutgers.jpg? | + | {{07-419434-a-tshirt-camp-scils-rutgers.jpg? |
The numbers you obtain from the book are 5.991 for the 0.05 probability and 9.210 for the 0.01 probability. They are called critical values. So the critical values are: | The numbers you obtain from the book are 5.991 for the 0.05 probability and 9.210 for the 0.01 probability. They are called critical values. So the critical values are: | ||
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| (O-T)< | | (O-T)< | ||
| Total | 40 | 40 | 20 | 100 | 2.73 | | | Total | 40 | 40 | 20 | 100 | 2.73 | | ||
- | **Chi-square value = The sum of the entire 6 yellow cells = 2.73.** | + | **Chi-square value = The sum of the entire 6 yellow cells = 2.73.** |
- | **Degrees of Freedom (df) = (the # of columns-1) x (the # of rows-1)= (3-1) x (2-1) = 2 x 1 = 2.** | + | **Degrees of Freedom (df) = (the # of columns-1) x (the # of rows-1)= (3-1) x (2-1) = 2 x 1 = 2.** \\ |
+ | \\ | ||
Look up the values in your textbook -- which is called " | Look up the values in your textbook -- which is called " | ||
+ | \\ | ||
They are: | They are: | ||
5.991 (0.05 probability) | 5.991 (0.05 probability) | ||
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In the first place, you assumed that there would be no differences in the abortion issue among the religious groups to get the expected values. And you compared the expected values to the observed values. In other words, you tested your survey result (the observed values) against the idea of "no difference." | In the first place, you assumed that there would be no differences in the abortion issue among the religious groups to get the expected values. And you compared the expected values to the observed values. In other words, you tested your survey result (the observed values) against the idea of "no difference." | ||
- | {{raritan-river-01.jpg? | + | {{raritan-river-01.jpg? |
- | + | ||
- | Therefore, it would not have been safe, had you ever said, "Sure 45% and 62.5% are different." | + | |
__Another note:__ You might have a question... Hey, wait a minute... If I pick up some other numbers from the chi-square distribution table, the result would be totally different! | __Another note:__ You might have a question... Hey, wait a minute... If I pick up some other numbers from the chi-square distribution table, the result would be totally different! | ||
- | + | <WRAP clear /> | |
- | *** For your information, | + | For your information, |
| df | .30 | .20 | .10 | .05 | .02 | .01 | .001 | | | df | .30 | .20 | .10 | .05 | .02 | .01 | .001 | | ||
| 1 | 1.074 | 1.642 | 2.706 | 3.841 | 5.412 | 6.635 | 10.827 | | 1 | 1.074 | 1.642 | 2.706 | 3.841 | 5.412 | 6.635 | 10.827 |
chi-square_test.1463355769.txt.gz · Last modified: 2016/05/16 08:12 by hkimscil