Question

x	P(x)
1	0.431
2	0.314
3	0.255

Find the mean and the standard deviation of the probability distribution.

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Answer 1

Solution:

x	P(x)	x * P(x)	x2 * P(x)
1	0.431	0.431	0.431
2	0.314	0.628	1.256
3	0.255	0.765	2.295
Sum	1	1.824	3.982

Mean = X * P(X)

= 1.824

Standard deviation =

=X ² * P(X) - ²

=  3.982 - (1.824)² = 0.65502

Standard deviation = = 0.8093