Question 1078065: In randomized, double-blind clinical trials of a new vaccine,
monkeys were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 123 of 445 subjects in the experimental group (group 1) experienced drowsiness as a side effect. After the second dose, 34 of
98 of the subjects in the control group (group 2) experienced
drowsiness as a side effect. Does the evidence suggest that a different proportion of subjects in group 1 experienced drowsiness as a side effect than subjects in group 2 at the
alpha α=0.10 level of significance?
What is the test statistic? z0= ??
what is the p value??
I was able to answer all the other parts of the questions besides this one so please help!
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! 2 sample proportion test
test statistic is a z. p1 hat is 0.276 and p2 hat is 0.349
if it is a two way test, which I would use, the critical value is -1.645.
z is -1.39
Fail to reject. p-value is 0.289; 0.0816 for a one way test
Note:
1. With a one way test (think in advance that there will be either no change or a change in one direction), the critical value is less, and one finds significance more often. This should not be used to find significant tests but should be determined in advance. It matters here because a one-way test would have a critical value of -1.282.
2. The formulae used are a two sample proportion test. (p1hat-p2hat)/sqrt ( p1(1-p1))/n1+p2(1-p2)/n2))
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