I have a probability distribution consisting of (x, p(x)): (-3, 0.1), (-2, 0.2), (-1, 0.3), (0, 0.05). The probabilities obviously do not sum to 1. How do I  find (average), (the second moment), (the variance)?

College Algebra
7th Edition
ISBN:9781305115545
Author:James Stewart, Lothar Redlin, Saleem Watson
Publisher:James Stewart, Lothar Redlin, Saleem Watson
Chapter9: Counting And Probability
Section9.4: Expected Value
Problem 1E: If a game gives payoffs of $10 and $100 with probabilities 0.9 and 0.1, respectively, then the...
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I have a probability distribution consisting of (x, p(x)): (-3, 0.1), (-2, 0.2), (-1, 0.3), (0, 0.05). The probabilities obviously do not sum to 1. How do I  find <x> (average), <x2> (the second moment), <sigmax2> (the variance)?

 

Expert Solution
Step 1

From the given information,

The probability distribution function as given below:

x P(X=x)
-3 0.1
-2 0.2
-1 0.3
0 0.05

As it is already given that sum of probability is not equal to one. Still required statistics can be solved as:

 

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