Question

17.1.33-T Question Help Based on data collected in 2010, 24 percent of women wanted to buy a certain brand of smart phone or tablet. Among men, 31 percent were interested in purchasing this brand. The survey contacted 238 women and 274 men. Complete parts (a) through (c) below. (a) Might the comparison between these two samples be confounded with a hidden factor? If so, identify such a factor. A. No, there are no hidden factors that could affect this comparison. B. Yes, possible factors are income, education, age, or job description C. Yes, possible factors are time of day and day of the week surveyed. D. Yes, possible factors are location, number of people surveyed, or internet access. (b) Find the 95% confidence interval for the difference, p - p2, between the proportion of women, p1, and the proportion of men, p2, interested in buying this company's device. The 95% confidence interval is (Round to three decimal places as needed.)

Answer 1

The statistical software output for this problem is:

Two sample proportion summary confidence interval: P1 : proportion of successes for population 1 P2: proportion of successes for population 2 P1-P2 : Difference in proportions 95% confidence interval results: Difference Count1 Totali Count2 Total2 Sample Diff. Std. Err. L. Limit U. Limit P1 - P2 57.12 238 84.94 274 -0.07 0.039332474 -0.14709023 0.0070902318

Hence,

95% confidence interval will be:

(-0.147, 0.007)