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# normal distribution z values

Maths and statistics discussion, revision, exam and homework help.

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1. normal distribution z values
Cn someone please explain how you work out the following probability

X~N(4.11, 0.19)

I can't seem to ge the right answer for this probability.

from the z tables i use values of 0.9803 for 2.06

and 0.8665 for 1.11,

so should the answer not be 0.9803-0.8665 ?

the answer in the book is 0.8468

any help appreciated, thanks
2. Re: normal distribution z values
(Original post by natalie_gs)
Cn someone please explain how you work out the following probability

X~N(4.11, 0.19)

I can't seem to ge the right answer for this probability.

from the z tables i use values of 0.9803 for 2.06

and 0.8665 for 1.11,

so should the answer not be 0.9803-0.8665 ?

the answer in the book is 0.8468

any help appreciated, thanks

It sounds like the calculation you're doing is this:

Can you see why?
3. Re: normal distribution z values
(Original post by Slumpy)

It sounds like the calculation you're doing is this:

Can you see why?
Oh yes, so it should be ;

?

thank you!
Last edited by natalie_gs; 20-06-2012 at 15:25.

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Last updated: June 20, 2012
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