Question

When designing a study to determine this population proportion, what is the minimum number of drivers you would need to survey to be 95% confident that the population proportion is estimated to within 0.04

Answer 1

Answer: 601

Step-by-step explanation:

The formula to find the minimum sample size(n) , if the prior population proportion is unknown:

$n=0.25(\dfrac{z^c}{E})^2$, where E = margin of error , $z^c$ = critical z-value for confidence level c.

Given : E  = 0.04

Z-value for 95% confidence = 1.96

So, the minimum sample size required = $0.25(\dfrac{1.96}{0.04})^2=0.25(49)^2$

$= 0.25\times 2401=600.25\approx601$

Hence, the minimum sample size required = 601