Wednesday

July 23, 2014

July 23, 2014

Posted by **John** on Thursday, March 10, 2011 at 2:20pm.

The NDSU library checks out an average of 320 books per day, with a standard deviation of 75 books. Suppose a simple random sample of 30 days is selected for observation.

What is the probability that the sample mean for the 30 days will be between 300 and 340 books?

Answer

0.4279

0.2128

0.8558

0.1064

0.9279

There is a 90% chance that the sample mean will fall below how many books?

Answer

323.5

416.0

342.5

337.5

443.4

- Stats 330- HELP -
**PsyDAG**, Friday, March 11, 2011 at 11:29amZ = (mean1 - mean2)/standard error (SE) of difference between means

SEdiff = √(SEmean1^2 + SEmean2^2)

SEm = SD/√(n-1)

If only one SD is provided, you can use just that to determine SEdiff.

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores.

**Related Questions**

Math - I need some help with this question. (5/x-2) = (6/x+6) + {29/(x-2)(x+6)} ...

Math - The Higgins Company sold the Northwest Company some machinery parts. The ...

US History - Hello! I have to do a project about a colony that became a state, ...

Math - lisa checks the stats for her favorite puzzle game on her Ipod. she sees ...

Algebra - I am having such a hard time in this class. Hopefully someone here can...

stats - Suppose a shipment of 500 machine parts contains 62 defective and 438 ...

Math - I missied school Friday and am not sure how to do my math homework. here ...

math - Please I need help: I need to figure out the procedure to this question: ...

chem h/w - i did a lab and i need to find out the melting point for lauric acid ...

Geometry Question plz help - Could someone please explain how to figure this out...