Question

Over the entire six years that students attend an Ohio elementary school, they are absent, on average, 28 days due to influenza. Assume that the standard deviation over this time period is σ = 9 days. Upon graduation from elementary school, a random sample of 36 students is taken and asked how many days of school they missed due to influenza.
What is the expected value for the sampling distribution of the number of school days missed due to influenza? A) 6 B) 9 C) 28 D) 168 2)

Answer 1

Answer:

C) 28

Step-by-step explanation:

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$, the sample means with size n of at least 30 can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$

Over the entire six years that students attend an Ohio elementary school, they are absent, on average, 28 days due to influenza.

By the Central Limit Theorem, the expected value is 28.

So the correct answer is:

C) 28