Confidence Intervals According to a national representative survey done by Consu
ID: 3021570 • Letter: C
Question
Confidence Intervals
According to a national representative survey done by Consumer Reports, you should always try to negotiate for a better deal when shopping or paying for services. Tips include researching prices at other stores and on the Internet, timing your visit late in the month when salespeople are trying to meet quotas, and talking to a manager rather than a salesperson. Suppose that random samples of 300 men and 300 women are taken, and that the men were more likely than the women to say they "always or often" bargained (30% compared with 25%). (Use p_1 and P_2 for the proportions of men and women, respectively, who say they "always or often" negotiate for a better deal.) Construct a 95% confidence interval for the difference in the proportion of men and women who say they "always or often" negotiate for a better deal. (Round your answers to three decimal places.)Explanation / Answer
p1 = 35% = 0.35 = proportion of women who always or often bargained
p2 = 25% = 0.25 = proportion of men who always or often bargained
Sample I Sample II Difference Sample p 0.35 0.25 0.1 n 300 300 Confidence interval mid point = 0.1 Std error for difference 0.031378 Margin of error = 0.0615 95% CI 0.0385-0.1615