we choose a sample of size 100 from a population of monthly cable bills having standard deviation $20 If we assume the population mean bill is $65, what is the probability mean of our sample is greater than $70.

Question

Dana Henson

Mathematics

24 May, 11:01

we choose a sample of size 100 from a population of monthly cable bills having standard deviation $20 If we assume the population mean bill is $65, what is the probability mean of our sample is greater than $70.

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Answers (1)

Know the Answer?

Jaylee Chang · Answer 1

0.0062

Step-by-step explanation:

Find the standard error.

σ = 20 / √100

σ = 2

Find the z-score.

z = (x - μ) / σ

z = (70 - 65) / 2

z = 2.5

Find the probability.

P (Z > 2.5) = 1 - 0.9938

P (Z > 2.5) = 0.0062