Chi-square test for statistical association

• Prob of selecting a person in drug group = 24/44


• Prob of selecting a person with improvement = 27/44


• Prob of selecting a person from drug group who had
  shown improvement= (24/44)*(27/44) = 0.3347
  (assuming two independent events)


• Expected value for cell (a) =0.3347*44 = 14.73