Question

9. True or False? A researcher compares the BMI of two populations of individuals from different socioeconomic backgrounds and finds that the proportion of individuals considered obese and from a poor background is.37 (n=112), and the proportion of individuals considered obese and from an affluent background is.27 (n = 87): a 95% confidence interval for the risk difference for obesity among members of the poor population compared to the affluent population is (-0.03, 0.23). n=112 1.96 P,=39 limle? Confidence intervals for relative risks and odds ratios require the usage of the

Answer 1

9. Answer: True

since

The confidence interval is (-0.03, 0.23)

We need to construct the 95% confidence interval for the difference between population proportions P1 - P2. We have been provided with the following information about the sample proportions: Sample Proportion 1 (Pi) = 0.37 Sample Size 1 (N) = 112 Sample Proportion 2 (P2) = 0.27 87 Sample Size 2 (N2) = The critical value for a = 0.05 is ze = 21-a/2 = 1.96. The corresponding confidence interval is computed as shown below: CI = P1 (1 - Pi) P1 - 22 – 21 p2(1 - P2) - P1-P2 + - Pi) P2(1 - P2) + Ni N N NO = 0.37 -0.27 - 1.96 X V 0.37(1 -0.37 112 0.271 -0.27) ..0.37 -0.27 + 1.96 x V 0.27(1 – 0.27) + 0.37(1 – 0.37) 112 + = (-0.029, 0.229)

Chapter 06) Multiple Choice:

Correct answer: Option (B)

since

We need to construct the 95% confidence interval for the population mean u. The following information is provided: Sample Mean X = Population Standard Deviation (0) = 1.3 Sample Size (N) = The critical value for a = 0.05 is ze = 21-a/2 = 1.96. The corresponding confidence interval is computed as shown below: cư - (*- *+ m) = (6.7 – 196-6.7 + 1.96-12) = (6.235, 7.165)