Question

The price of a particular camera is assumed to be a random variable with expected value $190 and standard deviation of $12. In a sample of 50 randomly selected stores, what is the probability that the sample mean falls within $4 of the expected value?

Answer 1

0.9817.

Explanation:

We are going to assume that this data is distributed based on the normal distribution.

Mean (population)= μ= $190

Standard deviation= σ= $12

n= 50

Meaning of "sample mean falls within $4": Sample value is between $186 and $194.

Check image below to see the calculation process:

Note: These values for probabilities can also be found in tables provides by book authors. You may ask your teacher/tutor about the and they will probably know where to find them.