Question

In Clinical trials of Liptor, 94 subjects were treated with Lipitor and 270 subjects were given the placebo. Among those treated with Lipitor, 7 developed infections. Among those given a placebo, 27 developed infections. We want to use a 0.05 significance level to test the claim that the rate of infections was the same for those treated with Lipitor and those given the placebo.

a) test claim using a hypothesis test

c) based on results is the rate of infection different for those treated with Lipitor?

Please do it out with the equation below. I am trying to understand it by hand rather than excel or SPSS first.

--> This is the equation i used. I got Z = -9.72 but i don't believe its right.

Answer 1

i am denoting Lipitor by and placebo by 2.

given data and some necessary calculations are:-

the pooled proportion be:-

a).hypothesis:-

test statistic be:-

b).p value :-

[ using normal distribution table]

[ if you use any software you will get 0.4638..which is more accurate]

c).decision:-

p value = 0.4654 >0.05 (alpha)

so, we fail to reject the null hypothesis.

we conclude that,

there is sufficient evidence to support the claim that the rate of infections was the same for those treated with Lipitor and those given the placebo at 0.05 level of significance.

based on the results we can not say that  the rate of infection was different for those treated with Lipitor.

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