Statistics practice question, can you explain?

Question

I'm trying to get a ready for a statistics final. Please answer this question as thoroughly as possible so I can get an idea of what to do.

A physician's health study of the effectiveness of aspirin in the reduction of heart attacks over 5 years found the following: Of 11,037 male medical doctors in the United States who took one 325 mg buffered aspirin tablet every other day, 104 suffered heart attacks. Of 11,034 male medical doctors in the United States who took a placebo 189 had heart attacks. Is there evidence that the proportion having heart attacks is significantly lower for the male medical doctors in the United States who received the buffered aspirin every other day vs. those who received a placebo? Does this lead you to believe that taking one aspirin is effective in reducing the incidence of heart attacks? Explain.

I need the statistical explination, not the regular logical explination. The standard deviation sounds right, but how did you get that answer exactly and why is it being used?

Answer 1

Yes. The standard deviation of the is about the square root.

That is 104+/- sqrt(104)

and

189 +/- sqrt(189)

These differ by more than 2 standard deviations

Answer 2

in my opinion the reduction of heart attacts in 85 doctors (189-104=85) taking the aspirin is pretty good method in lowering the # of heart attacts... Also in comparing it with how many doctors were involved it improved almost by 1% ... pretty big number if you take it nationally

Answer 3

I'm not sure. Maybe the aspirin is inert and the "placebo" has the effect of raising the likelihood of heart attacks.

Answer 4

error square root of n so that is sqrt(11034)=105
so the difference could be random chance. If you need somthing more sofisticated you should ask in mathimatics topic.