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# what should I do in this situation (S1 normal distribution) Watch

1. when I get to the point in the question where I have to find these probabilities:

P(Z > 1.625) or P(Z > 1.66666666666666667) or P(Z > 0.9315789...)

Do I always round each of those numbers to 2 decimal places, so that I could find their probabilities using the 'normal distribution function' table?

because as you know, in that table, probabilities are only given for values of 'a' in P(Z > a) where 'a' is in 2dp.
2. (Original post by W.H.T)
when I get to the point in the question where I have to find these probabilities:

P(Z > 1.625) or P(Z > 1.66666666666666667) or P(Z > 0.9315789...)

Do I always round each of those numbers to 2 decimal places, so that I could find their probabilities using the 'normal distribution function' table?

because as you know, in that table, probabilities are only given for values of 'a' in P(Z > a) where 'a' is in 2dp.
Yes. Well, you always try to get the most accurate answer possible. So for example:

Let's say you wanted to find P(Z > 1.235). From the table, you know that (I'm making these numbers up btw, they are not actually right!!):
P(Z > 1.23) = 0.214
P(Z > 1.24) = 0.212
Then the answer you should give is 0.213. You'll probably get docked a mark if you rounded P(Z > 1.235) to = P(Z > 1.24) = 0.214.

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Updated: December 24, 2010
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