Question

QUESTION 10 · 1 POINT The average American city has 50 buses that use green energy, with a standard deviation of 5 buses. A city planner is interested in the sample mean number of buses for a sample of 30 cities. He calculates that: и My 50 V30 = 9.13 and II 0x 5 30 = 0.91 What did he do wrong? Select the correct answer below: O He didn't do anything wrong. The correct answer is Hi = 9.13 and 0; = 0.91. O He had the mi wrong, but calculated of correctly. He should have had: Mi 50 and on = 0.91. He unnecessarily divided oz by vñ and should have had: Mi = 9.13 and a = 5 O He did not need to divide u or o by vñ, and should have had: Mi = 50 and a = 5

Answer 1

For the given question :

$\mu_{\overline{x}}=\mu = 50$

$\sigma_{\overline{x}}=\frac{\sigma}{\sqrt{n}}= \frac{5}{\sqrt{30}}=0.91$

The mistake is only in the calculation of $\mu_{\overline{x}}$ and $\sigma_{\overline{x}}$ is correct so option (b) is correct.