A clinical trial is run to investigate the effectiveness of an experimental drug

Question

A clinical trial is run to investigate the effectiveness of an experimental drug in reducing preterm delivery to a drug considered standard care and to placebo. Pregnant women are enrolled and randomly assigned to receive either the experimental drug, the standard drug or placebo. Women are followed through delivery and classified as delivering preterm (< 37 weeks) or not. The data are shown below.

Preterm Delivery

Experimental Drug

Standard Drug

Placebo

Yes

17

23

35

No

83

77

65

The c2 test statistic for the above data is 8.953.

Based on the c2given above, is there a statistically significant difference in the proportions of women delivering preterm among the three treatment groups at an a=0.05.

A researcher suspects that the actual prevalence of generalized anxiety among children and adolescents is higher than the previously reported prevalence of generalized anxiety disorder among children and adolescents. The previously reported prevalence of generalized anxiety disorder among children and adolescents is 3.9%, and the researcher conducts a study to test the accuracy of the previously reported prevalence of generalized anxiety disorder by recruiting 98 children and adolescents from various pediatricians’ offices and tests them for generalized anxiety disorder using the DSM-5. The researcher determines that the prevalence of generalized anxiety disorder among the participants of the study is 6.1%. The researcher’s hypothesis, for a level of significance of 5%, should resemble which of the following sets of hypothesis?

H0: p > .039; H1: p = .039; alpha= .05

H0: p = .039; H2: p > .039; alpha= .05

H0: p > .039; H1: p = .039; alpha= .95

H0: p = .039; H2: p > .039; alpha= .95

Referring to the previous question, for a level of significance of 5%, what should the researcher’s decision rule look like? (1 point)

Reject H0 if z is less than or equal to -1.645.

Reject H0 if z is greater than or equal to 1.645.

Reject H0 if z is less than or equal to -1.96.

Reject H0 if z is greater than or equal to 1.96.

Preterm Delivery

Experimental Drug

Standard Drug

Placebo

Yes

17

23

35

No

83

77

65

Explanation / Answer

Since we need to test if prevelance is higher than reported, our hypotheses will be:

H0: p = .039; H2: p > .039; alpha= .05

Decision rule for a right tailed test with 0.05 level of significance:

Reject H0 if z is greater than or equal to 1.645.

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