For a 2x2 Contingency Table:
 ·Rates, Risk Ratio, Odds, Odds Ratio, Log Odds
 ·Phi Coefficient of Association
 ·Chi-Square Test of Association
 ·Fisher Exact Probability Test


For two groups of subjects, each sorted according to the absence or presence of some particular characteristic or condition, this page will calculate standard measures for Rates, Risk Ratio, Odds, Odds Ratio, and Log Odds. It will also To proceed, enter the values of X0Y1, X1Y1, etc., into the designated cells. When all four cell values have been entered, click the «Calculate» button. To perform a new analysis with a new set of data, click the «Reset» button.
The logic and computational details of the Chi-Square and Fisher tests are described in Chapter 8 and Subchapter 8a, respectively, of Concepts and Applications. A briefer account of the Fisher test will be found toward the bottom of this page.

Data EntryT
X Expected Cell
Frequencies per
Null Hypothesis
0 1 Totals
  Y     1  
  0  
Totals
   Calculate         Reset   

 Rate   Risk 
 Ratio 
 Odds   Odds 
 Ratio 
 Log 
 Odds 
 Group 1 
 Group 2 
Rate = proportion in group with condition present
Risk Ratio = Rate[1]/Rate[2]
Odds[1] = present[1]/absent[1]
Odds[2] = present[2]/absent[2]
Odds Ratio = Odds[1]/Odds[2]
Log Odds = natural logarithm of Odds Ratio

  .95 Confidence Intervals  
 Observed    Lower  
Limit
 Upper 
Limit
 Risk Ratio 
 Odds Ratio 

 Chi-Square 
Chi-square is calculated only if all
expected cell frequencies are equal
to or greater than 5. The Yates value
is corrected for continuity; the Pearson
value is not. Both probability estimates
are non-directional.
 Phi    Yates    Pearson 
 P 

Fisher Exact Probability Test:T
  P    one-tailed
 two-tailed


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