NORMDIST function in excel giving values greater than 1

1. NORMDIST function in excel giving values greater than 1

Hi,

I'm using the normdist function with 'false' argument to generate a probability density function: NORMDIST(0.04,0,0.3,FALSE) is giving a value greater than 1 which can't be correct since this function is supposed to return a probability. Has anyone seen this before?

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2. Normdist

When using the "false" option, divide the result by 100.  Register To Reply

3. When using the "false" option, divide the result by 100.
That's not even wrong.

NORMDIST(x, mean, dev, FALSE) does not return a probability; it returns the density function, which is the slope of the cumulative distribution function. For a continuous variable, the probability of any particular value is zero, because there are an infinite number of values.

If you want to know the probability that a continuous random variable with a normal distribution falls in the range of a to b, use

= NORMDIST(b, mean, dev, TRUE) - NORMDIST(a, mean, dev, TRUE)

The peak value of the density function occurs at the mean (i.e., =NORMDIST(mean, mean, dev, FALSE) ), and the value is

=1 / (SQRT(2 * PI()) * dev)

The peak value will exceed 1 when the deviation is less than 1 / sqrt(2pi) ~ 0.399.  Register To Reply

4. Re: NORMDIST function in excel giving values greater than 1

You tha bomb shg! Thanks!  Register To Reply