# statistics

I cant figure this out!!!

The income of trainees at a local mill are normally distributed with a mean of \$1100 and a standard deviation of \$150. If a sample of 100 trainees is selected, what is the probability that the sample mean will be less than \$1075 month?

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1. The standard error (SE) of the mean is the standard deviation (SD) divided by the square root of the number in the sample.

In this case, your Z score would be (\$1075-\$1100)/SE. Find the Z score and look it up in the back of your statistics text in a table labeled something like "areas under the normal disrtibution."

I hope this helps. Thanks for asking.

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posted by PsyDAG
2. Still don't get it...sorry. I am really trying to get it without asking for the answer, but I just don't get it. Help please.....

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posted by Denim
3. Your SE = SD/sq.root of n

SE = 150/10 = 15

For a distribution of sample means, the Z score = (1075-1100)/15.

Can you calculate the Z score and use it in the table to find the probability?

I hope this helps a little more. Thanks for asking.

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posted by PsyDAG

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