Math 110 - Module 5 Exam
Portage Learning
Question 1
Suppose that you take a sample of size 18 from a population that is not normally distributed.
Can the sampling distribution of \( \bar{x} \) be approximated by a normal probability
distribution?
Answer: No, the sampling distribution of \( \bar{x} \) cannot be approximated by a
normal probability distribution because the population is not normally distributed, and
the sample size is less than 30.
Question 2
Suppose that you are attempting to estimate the annual income of 1100 families. In order to
use the infinite standard deviation formula, what sample size (\( n \)) should you use?
Answer: To determine the sample size:
n / N ≤ 0.05
N = 1100
n ≤ 0.05 × 1100
n ≤ 55
The sample size (\( n \)) should be less than or equal to 55.
Question 3
Suppose you are using a 95% confidence interval to estimate the population mean, and the
standard deviation of the population is 12. The sample size is 64. What is the margin of
error?
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