Main content

Statistics and probability

Unit 10: Lesson 3

Sampling distribution of a sample mean

Finding probabilities with sample means

AP.STATS: UNC‑3 (EU), UNC‑3.S (LO), UNC‑3.S.1 (EK)

You might need: Calculator,Z table

Houseflies have pretty short lifespans. Males of a certain species have lifespans that are strongly skewed to the right with a mean of 26 days and a standard deviation of 12 days. A biologist collects a random sample of 9 of these male houseflies and observes them to calculate the sample mean lifespan.

What is the probability that the mean lifespan from the sample of 9 houseflies x, with, \bar, on top is less than 24 days?

Choose 1 answer:

(Choice A)
P, left parenthesis, x, with, \bar, on top, is less than, 24, right parenthesis, approximately equals, 0, point, 31
(Choice B)
P, left parenthesis, x, with, \bar, on top, is less than, 24, right parenthesis, approximately equals, 0, point, 35
(Choice C)
P, left parenthesis, x, with, \bar, on top, is less than, 24, right parenthesis, approximately equals, 0, point, 39
(Choice D)
P, left parenthesis, x, with, \bar, on top, is less than, 24, right parenthesis, approximately equals, 0, point, 43
(Choice E)
We cannot calculate this probability because the sampling distribution is not normal.

Stuck?

Statistics and probability

Unit 10: Lesson 3

Problem