Q:

A political interest group wants to determine what fraction p ∈ (0, 1) of the population intends to vote for candidate A in the next election. 1000 randomly chosen individuals are polled. 457 of these indicate that they intend to vote for candidate A. Find the 95% confidence interval for the true fraction p.

Accepted Solution

A:
Answer:95% confidence interval for the true fraction p is (0.426, 0.488) Step-by-step explanation:Confidence Interval can be calculated using pΒ±ME where p is the sample proportion ([tex]\frac{457}{1000} =0.457[/tex]ME is the margin of error from the mean and margin of error (ME) around the mean can be found using the formulaME=[tex]\frac{z*\sqrt{p*(1-p)}}{\sqrt{N} }[/tex] where z is the corresponding statistic in 95% confidence level (1.96)p is the sample proportion (0.457)N is the sample size (1000) then ME=[tex]\frac{1.96*\sqrt{0.457*0.543}}{\sqrt{1000} }[/tex] β‰ˆ 0.031Then 95% confidence interval would be 0.457Β±0.031 or (0.426, 0.488)