Thanks in advance,

Denise

- Thread starter BestNurse
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Thanks in advance,

Denise

To be frank, I'm not really sure what the question is asking when it says: "in the middle 70% range".

However, we do have:

mu = $36

sigma = $3.50

and what you tried to compute sounds like the 35th percentile and 65th percentile.

However, your value for z should then be 0.39

If you look in the table you should see for 0.39 the value 0.6517, and the value for -0.39 is 0.3482 (which is about 1 - 0.6517)

Not sure what you did.

David

Anyone else have an opinion on this question? I am still not sure of how to work it out and I am pretty certain what I have done is not correct.

Thanks,

Denise

Thanks,

Denise

What could help is to have the whole problem statement in context. Does it appear in a textbook? If so, the name of the chapter, and the section can help to figure out what the problem is asking you to apply.

Posting the whole problem statement verbatim may help to understand what is going on.

David

and what you tried to compute sounds like the 35th percentile and 65th percentile.

take a look at this table:

http://www.science.mcmaster.ca/psychology/poole/z-table2.jpg

Last edited:

Thanks,

Denise

Thanks in advance,

Denise

M = 36

SD = 3.5

Find 70% confidence interval.

Shouldn't be too tough. You can check your answer using the bottom calculator on this page:

http://davidmlane.com/hyperstat/z_table.html

Edit: Yep, looks like you have the right answer, within rounding error.

This is my reading of the question:

M = 36

SD = 3.5

Find 70% confidence interval.

Shouldn't be too tough. You can check your answer using the bottom calculator on this page:

http://davidmlane.com/hyperstat/z_table.html

Edit: Yep, looks like you have the right answer, within rounding error.

M = 36

SD = 3.5

Find 70% confidence interval.

Shouldn't be too tough. You can check your answer using the bottom calculator on this page:

http://davidmlane.com/hyperstat/z_table.html

Edit: Yep, looks like you have the right answer, within rounding error.

I think this sort of makes sense within the context of the problem because maybe sometimes demand for the product is low, and so they decrease the price, and sometimes demand for the product is high, and so they increase the price (but they don't want to increase or decrease the price beyond certain bounds)

David