In a World Atlas study, 10% of people have blue eye color. Lane decided to observe 35 people and she concluded 5 people had blue eyes. Calculate the z-score.
A) 0.1428
B) 0.0430
C) 0.8452
D) 0.0041

Question

Quizplus · Accepted Answer

The z-score is calculated using the formula $z = \frac{(X - \mu)}{\sigma}$, where $X$ is the observed frequency, $\mu$ is the expected frequency, and $\sigma$ is the standard deviation of the expected frequency. Here, $X = 5$, $\mu = 10\% \times 35 = 3.5$, and $\sigma = \sqrt{35 \times 0.1 \times (1 - 0.1)} = \sqrt{3.15} \approx 1.7748$. Thus, $z = \frac{(5 - 3.5)}{1.7748} \approx 0.8452$.

In a World Atlas Study, 10% of People Have Blue