For hypothesis tests, please give me the null and alternative hypotheses, the fo
ID: 3296902 • Letter: F
Question
For hypothesis tests, please give me the null and alternative hypotheses, the formula for the test statistic, the appropriate substitutions, the value of the test statistic, the rejection region (be careful on two-sided tests, don’t forget both tails) or p-value (Note: This means you can use either approach, unless specified), whether you accept or reject the null, and the interpretation of the results in the words of the problem. For confidence and prediction intervals, give the formula used for the interval, the appropriate substitutions, the actual interval(s), and interpret it in the context of the problem.
9) A researcher wishes to test the effect of a particular blood pressure drug. A random sample of 11 patients were enrolled into the study and given the medication. Blood pressure data was collected prior to receiving the drug and again after administration. Unfortunately, the actual data was lost and all that remains are records of the direction of the change (that is if the difference was <0, =0, or >0). Suppose 2 patient experienced no change, 2 patients’ blood pressures went up, and the rest, 7, went down. At the 10% level, is there enough evidence to conclude the drug is effective at lowering blood pressure, that is, is the median change less than 0?
Explanation / Answer
Sign Test for median:
H0:md=0
H1:md<0
Given that n=11
But there is no change for 2 patients ,so n=9
n+=2,n-=7
It is Binomial distribution with n=9,p=0.5
p-value=P(x<=2)=BINOMDIST(2,9,0.5,TRUE)=0.089
Significance level=0.1
As,p-value < 0.1 ,we reject H0.
There is enough evidence to conclude that the drug is effective at lowering blood pressure.
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