1. The problem statement, all variables and given/known data In a study of effecftiveness of an antipsychotic drug, patients are treated with the antipsychotic drug and were compared to those receiving a placebo. In terms of the number relapsing, 698 of 1068 patients were released after taking the placebo while 639 out of 2,127 relapsed after taking the antipsychotic drug, Test the prediction that the antipsychotic drug is significantly more ffective in preventing relapse than placebo.(Have to apply Chi-square) 2. Relevant equations What should the Ho and H1 be? 3. The attempt at a solution As I know, the Ho should be that the observed data follows some theoretical model and any deviation(which will almost always be) is due to chance. But here since we have no theoretical model to compare our data with I have thought in this way: Since H1 is often the hypothesis that the scientist is trying to prove and the Null could be set as what might be needed to disprove1? So, Ho= The effect of antipsychotic drug and the placebo is the same, any deviation/difference is due to chance. Ha= The effect of antipsychotic drug and the placebo is not the same and the drug is significantly more effective. 1 This is what I presume, tell me if it isn't right (ideally with citation).