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# Sharp EL 9900 Calculator for Probability and Normal Distributions watch

1. Does anyone know how to find the probability, say P(Z <1), using the above mentioned calculator.

I have tried STAT DISTR pdfnorm(1) but it comes up with 0.2419.... instead of 0.84134.

I can't find anything else in the manual.
2. I don't know this calculator, but to find P(Z<1) you need to look for a function that looks like "cdf" (cumulative distribution function) rather than pdf. The pdf function will give you the value of the normal bell curve at Z=1, but that's not P(Z<1), for which you need the cumulative version.
3. (Original post by old_engineer)
I don't know this calculator, but to find P(Z<1) you need to look for a function that looks like "cdf" (cumulative distribution function) rather than pdf. The pdf function will give you the value of the normal bell curve at Z=1, but that's not P(Z<1), for which you need the cumulative version.
Thank you. I didn't know what pdf and cdf stood for so that has been a great help in itself. I have now found cdfnorm(lower limit, upper limit [, mean, standard deviation]). when I enter (0,2) it gives me a value that I then need to add 0.5 to for the other half of the curve, as it were. I can live with that as it seems there isn't a function that will give me everything to the left of 2.

I'll just have to think harder won't I.

4. You should also be able to include the left hand half of the curve by typing in a large negative number, e.g. -1E6 as your lower limit.
5. Yes, that worked. What a gem you are.

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