Researchers Jemmott III et al. (Journal of American Medical Association) reporte

Question

Researchers Jemmott III et al. (Journal of American Medical Association) reported a study in which a group of inner-city African American adolescents from Philadelphia were randomly divided into three groups as part of an experiment to assess the effectiveness of different HIV prevention programs. One group was given "abstinence HIV intervention," the next group was given "safer-sex HIV intervention," and the third group was given "health promotion intervention," which was to serve as a control. One outcome that was measured was whether subjects who were sexually active during a three-month period reported consistent condom use.

a. State the appropriate null and alternative hypotheses in words.

b. Explain why it would be okay to use the theory-based method to find a p-value for this study.

c. Use an appropriate applet (for example, the Multiple Means applet) to find and report the following:

-The name of the statistic and its numeric value

-The theory-based p-value

Explanation / Answer

Hello,

Here data is divided in three different groups as per randomization,

And the outcome is continocon , so most esiaste way to analyze the above problem is ANOVA .

A) null-. All methods of HIV prevention are equally effective

Alt - There is difference between the two treatments as cmpaica to control .

B) to find the theory based p-values it's ok be course theory based p-values gives the approximate value for the study . If we want to calculate the exact p-values then we must have go with software package .

C) in the ANOVA we use the F Statistics , which is the ratio of the two chi-square statistics. So in the analysis of variance the denominator is total variance and the numerator is between treatment variance . F value near to 1 , then there is lack of avoidance against the null hypothesis .

- to calculate the p value we have to fix the significance level first suppose we are testing the above problem for the 0.05 level of significance .

If the thoert based p-values is less then 0.05 then we reject the null hypothesis .

There is some advanced tecqnice to solve a such a problem

1) generalized mixed model - this is advanced regression tecqnice where treatments and time are independent variables and outcome is dependent variable . From above same method we can use such a tecqnice and alive the problem.

Thanks

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