When to use just norm.dist and when to subtract from one ? The key is remembering that Excel adds up from the LEFT of the distribution. So =norm.dist() will give you the probability smaller than whatever value for X you have put into the data. If you wanted 'greater' than some X value, then you must subtract from 1.
Example: the mean is 350, the standard deviation is 10. Find the probability of getting a value smaller than 335.
Solution: the question is asking us to find the probability of 335 or less. So = norm.dist(335, 350, 10, true) = 0.067 (rounded).
Example: what is the probability of finding a probability of 370 or more..... now we want the area to the RIGHT of 370 in the distribution. So first find =norm.dist(370, 350, 10, true) = 0.98. And now subtract from 1 to give 1 - 0.98 = 0.02.
Note that with norm.dist we always use 'true'. The functions I've been using are for Excel 2010. For older versions of Excel, you miss out the dot.
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