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chi-square_test [2016/05/16 08:21]
hkimscil
chi-square_test [2016/05/16 08:21] (current)
hkimscil
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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;​ called degree of freedom), you would be able to obtain the values of the other four cells without consulting the actual observed values. 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;​ called degree of freedom), you would be able to obtain the values of the other four cells without consulting the actual observed values.
  
-{{07-419434-a-tshirt-camp-scils-rutgers.jpg?​202 |RUSURE campaign SCILS Rutgers 2000}} Anyway, you just obtained the chi-square value (37.58) and the degrees of freedom (2). You can look up the text book (for chi-square test): (1) find your degrees of freedom (2), that is, the second row of the table; (2) decide the probability you want to employ (usually .05 or .01); (3) write down the numbers; and (4) compare them to your chi-square value. (see [[:chi square distribution table]])+{{07-419434-a-tshirt-camp-scils-rutgers.jpg?​202 |RUSURE campaign SCILS Rutgers 2000}} Anyway, you just obtained the chi-square value (37.58) and the degrees of freedom (2). You can look up the text book (for chi-square test): (1) find your degrees of freedom (2), that is, the second row of the table; (2) decide the probability you want to employ (usually .05 or .01); (3) write down the numbers; and (4) compare them to your chi-square value. (see [[:chi-square distribution table]])
  
 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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 __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 /> <WRAP clear />
-For your information,​ the table looks as follows. And the chi-square value you got from your data was 2.73 (see [[:Chi square distribution table]]).+For your information,​ the table looks as follows. And the chi-square value you got from your data was 2.73 (see [[:Chi-square distribution table]]).
 | 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.txt · Last modified: 2016/05/16 08:21 by hkimscil