The results of a recent poll on the preference of shoppers regarding two products are shown below. $$\begin{array} { l l l }
\text { Product } & \text { Shoppers Surveyed } & \text { Shoppers Favoring } \
& & \text { This Product } \
\text { A } & 800 & 560 \
\text { B } &900 & 612
\end{array}$$ The 95% confidence interval estimate for the difference between the populations favoring the products is
A) -.024 to .064.
B) .6 to .7.
C) -.024 to .7.
D) .046 to .066.

Question

The results of a recent poll on the preference of shoppers regarding two products are shown below. $$\begin{array} { l l l } 
\text { Product } & \text { Shoppers Surveyed } & \text { Shoppers Favoring } \
& & \text { This Product } \
\text { A } & 800 & 560 \
\text { B } &900 & 612
\end{array}$$   The 95% confidence interval estimate for the difference between the populations favoring the products is
A) -.024 to .064.
B) .6 to .7.
C) -.024 to .7.
D) .046 to .066.

Quizplus · Accepted Answer

The confidence interval for the difference in proportions is calculated using the formula for the difference between two independent proportions. The interval is calculated as (p1 - p2) ± Z * sqrt((p1(1-p1)/n1) + (p2(1-p2)/n2)), where p1 and p2 are the sample proportions, n1 and n2 are the sample sizes, and Z is the Z-value for the desired confidence level. The calculation results in the interval -.024 to .064.

The Results of a Recent Poll on the Preference of Shoppers