Section1:
2 x 2 Tables
Chi-Square
Degrees of Freedom
p-Value Flip
Coin 100 times
Breast Cancer Example
Breast Cancer Example
The chi-square test procedure can also be used to test whether two categorical variable are associated, that is, whether they are related other than by chance.
Snedecor and Cochran 127 (8th ed. 1989) reports the results
of Murphy and Abbey’s early study of whether breast cancer tends
to run in families:
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| Breast Cancer in Mother |
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| No Breast Cancer in Mother |
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| Totals |
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Here the 
statistic is 1.641, with one degree of freedom, corresponding to a p-value
of 0.20.
Question
Should we conclude that there is no association between breast cancer in mother and daughter? Why?
