Question

When we know population data, but have a sample to work with, we use the formula...

When we know population data, but have a sample to work with, we use the formula above to compute a Z score.

  1. If the cholesterol level of men in the community is normally distributed with a mean of 200 and a standard deviation of 25, what is the probability that a randomly selected sample of 49 men will have a mean between 190 and 205?

Homework Answers

Answer #1

Solution :

Given that,

mean = = 200

standard deviation = = 25

= / n = 25 / 49 = 3.5714

= P[(190 - 200) / 3.5714 < ( - ) / < (205 - 200) / 3.5714)]

= P(-2.8 < Z < 1.4)

= P(Z < 1.4) - P(Z < -2.8)

= 0.9192 - 0.0026

Probability = 0.9166

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