Probability Distribution Help...

mommaT2u

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Jul 28, 2010
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Here's my problem:
In this exercise, assume that the readings on the thermometers are normally distributed with a mean of 0 degrees and a standard deviation of 1.00 degrees C. Find the indicated probability, where Z is the reading in degrees.

P(z < -2.575 or z < 2.575)

OK, this is what I have but it ended up being wrong, maybe someone could tell me where I went wrong or if I have no clue at all.

P(z < -2.575 or z < 2.575) =

P(z < -2.575) + P(z < 2.575) =

to find the z Score I used the following formulas:
-2.575 - 0 / 1 = -2.575 which is what you need to convert to a z Score of .0049.
2.575 - 0/ 1 = 2.575 which is what you need to convert to a z Score of .9948

I then would take .9948 and add it to .0049 to get .9997 which is wrong...it should be .0100

Any and all help is appreciated, thank you in advance...MommaT
 
\(\displaystyle P(-2,575<z<2.575)\) corresponds to a 99% confidence interval.

Thus, 1-.99=.01
 
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