Overview: This short paper assignment will help you understand how confidence intervals provide us with information on how well a sample represents a population and helps us to answer specific types of research questions.

A study was done looking at communication between adolescents with asthma and their health care provider. Forty-six providers from four pediatric practices in North Carolina agreed to participate in the study. Two clinics were in rural areas and two were in suburban areas of North Carolina. Adolescent patients who agreed to participate were randomized, along with their caregiver, into either the intervention group or the usual care group. The intervention group watched a video on an iPad and then completed an asthma question prompt list before their visits. All visits were audiotape recorded. A secondary analysis of transcripts from these medical visits of adolescents, ages 11-17 years, discovered that 44% (81 out of 185) of the adolescents and/or their providers from the intervention group discussed tobacco smoking in a visit versus 32% (56 out of 174) in the control group.

From these results we can compute 3 different 95% confidence intervals using the sample proportions (p) from this study.

a) For estimate, pi = 0.44, 95% CI: (0.37, 0.51)

b) For estimate, pc = 0.32, 95% CI: (0.25, 0.39)

c) For estimate, pi - pc = 0.44 -0.32 = 0.12, 95% CI: 0.02, 0,22)

Prompt: After reading the short paper scenario and using the information provided, complete the steps below.

Part I

1. Describe the population that this sample was selected from.

2. Write out the research question that can be answered by the confidence interval (CI) in (a).

3. Describe in words the population parameter that is being estimated by the confidence interval in (a).

4. What is the margin of error for the confidence interval in (a)?

5. Interpret the CI in (a) using your own words. What answer is it giving us in regard to the research question?

Part II

1. Write out the research question that can be answered by the confidence interval in (c).

2. Describe in words the population parameter that is being estimated by the confidence interval in (c).

3. What is the margin of error for the confidence interval in (c)?

4. Interpret the confidence interval in (c) using your own words. What answer is it giving us in regard to the research question?