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Drongoski

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Easier with a diagram of course.
The Normal curve is symmetrical about z = 0.

P(-N <= z <= N) = P(-N <=z <= 0) + P(0 <= z <= N) = 0.1 + 0.1.
P(z <= N) = 0.6 = P(z <= 0 ) + P(0 <= z <= N) = 0.5 + P(0 <= z <= N)
Therefore P(0 <= z <= N) = 0.1 also = P(-N <= z <= 0) by symmetry.
 

5uckerberg

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Alright, time for the explanation. Here, , so the negation is . Since N is a number that is not zero and for the Gaussian curve the mean is at 0.5 which is the centre of the curve and it can be found as . Now, for we could just bring up the fact that , and say the negation is and note the Gaussian curve is an even function so in response this is going to give us 0.2 because their negations when added together give 0.8 and logically speaking 1-0.8=0.2

The Gaussian curve is the curve that will give us the whole curve as 1.
 
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CM_Tutor

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Alright, time for the explanation. Here, , so the negation is . Since N is a number that is not zero and for the Gaussian curve the mean is at 0.5 which is the centre of the curve and it can be found as . Now, for we could just bring up the fact that , and say the negation is and note the Gaussian curve is an even function so in response this is going to give us 0.2 because their negations when added together give 0.8 and logically speaking 1-0.8=0.2

The Gaussian curve is the curve that will give us the whole curve as 1.
The part in green should say that the Gaussian has the mean at 0, meaning half of the distribution is below zero.

I'm sure @5uckerberg meant this, I just want to make sure anyone reading it who isn't sure isn't confused by the typo. :)
 

5uckerberg

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The part in green should say that the Gaussian has the mean at 0, meaning half of the distribution is below zero.

I'm sure @5uckerberg meant this, I just want to make sure anyone reading it who isn't sure isn't confused by the typo. :)
Oh yes, the mean is halfway. I used 0.5 as a reference for halfway. Since the total area for the Gaussian curve is 1. I can see where people get confused. The mean at zero refers to z scores which are denoted by N.
 
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CM_Tutor

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I see what you meant... the mean is at z = 0 by which point the cumulative probability / area is 0.5. I didn't read it the way you intended at first, so I recognise now that it can be read literally and be correct. :)
 

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