Find the Sum of Cumulative Proability in Excel

Question

Im wondering how I would calculate the Sum of a Cumulative Probability in Excel?

I have attached the column of values that I am working with. Any help is appreciated

I have tried finding the mean/average of the values and then std deviation, then using the norm distribution function and then sum those values but it doesn't seem to be creating the right value.

Answer 1

You can use NORM.DIST(x,mean,standard_dev,cumulative) which allows you to specify the mean and the standard deviation. If the last argument is TRUE it returns the cumulative probability. Obviously, under the assumption, the distribution of your data corresponds to the Normal Distribution. If you are not sure about that, then you need to run a normality test that will confirm that first (anyway most natural phenomenons are distributed as Normal).

For the mean, you can use the AVERAGE function, and for the Standard Deviation STDEV.S.

So on cell D4 put the following formula to calculate the cumulative probability for 0.25:

=NORM.DIST(D3,D1,D2, TRUE)

So if your data correspond to a Normal Distribution, then the cumulative probability for 0.25 will be 0.361494.