Question

Researchers studied the effect of a novel pneumococcal vaccine on pneumonia in elderly adults. Of 200 elderly adults who took the vaccine, 20 developed pneumonia within a year while 180 did not. Of 80 elderly adults who did not take the vaccine, 20 developed pneumonia while 60 did not. For the following questions, test for an association between the vaccine and pneumonia at the alpha=0.05 level. Calculate chi square

Answer 1