Question

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 (25% compared with 20%). (Use p1 and p2 for the proportions of men and women, respectively, who say they "always or often" negotiate for a better deal.) (a) 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.)

=to=

Answer 1

From the given information we have

x₁ = number of men who say  they "always or often" negotiate for a better deal = 0.25*300 = 75

x₂ = number of women who say  they "always or often" negotiate for a better deal = 0.20 * 300 = 60

Let's used minitab to construct confidence interval of men and women who say they "always or often" negotiate for a better dea.

Step 1) Click on Stat>>>Basic statistics>>>2-proportions...

Step 2) select summarized data

Fill the required information and then click on Option and again fill the required information

Look the following image

Then click on OK and again click on OK

So we get the following output

From the above output the 95% confidence interval for the difference in the proportion of men and women who say they "always or often" negotiate for a better deal is from  -0.017 to 0.117