Question

) when 490 college students were surveyed, 130 said they own their car. construct a 95% confidence interval for the proportion of college students who say they own their cars

Answer 1

Proportion of those who own a car (P) = 130/490 = 0.2653
At 95% confidence, Z = 1.96
Sample size (N) = 490

Confidence interval = P+/- Z*Sqrt (P(1-P)/N) = 0.2653+/- 1.96*Sqrt (0.265(1-0.265)/490) = 0.2653+/-0.0199

Therefore, for any randomly selected student (x), the probability that he/she owns a car is;

0.2454 ≤ x ≤ 0.2852