I need help with finding the Mean and the Sigma 2 can anyone explain to me how this is done????

Let the pmf of X be defined by :----------> x|0|1|2|3|

f(x) |.2|.3|.4|

Compute M and O2

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- October 10th 2007, 02:37 PMballinisahobbyProb & Stats
I need help with finding the Mean and the Sigma 2 can anyone explain to me how this is done????

Let the pmf of X be defined by :----------> x|0|1|2|3|

f(x) |.2|.3|.4|

Compute M and O2

- October 11th 2007, 05:52 AMTKHunny
Unfortunately, you have not supplied the entire distribution. You have four values, but only three probabilties. There remain 10% missing.

For the mean, simply multiply and add

Value * Probability of the Value

For the Variance, it is only slightly different. Add these:

(Value^2) * Probability of the Value - October 14th 2007, 01:38 PMballinisahobby
well part of the problem is finding that missing probability. How would you go about doing that?