Finite Math Examples

Find the Standard Deviation table[[x,P(x)],[-1,1/3],[0,1],[1,3],[2,9],[3,27]]
xP(x)-113011329327
Step 1
Prove that the given table satisfies the two properties needed for a probability distribution.
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Step 1.1
A discrete random variable x takes a set of separate values (such as 0, 1, 2...). Its probability distribution assigns a probability P(x) to each possible value x. For each x, the probability P(x) falls between 0 and 1 inclusive and the sum of the probabilities for all the possible x values equals to 1.
1. For each x, 0P(x)1.
2. P(x0)+P(x1)+P(x2)++P(xn)=1.
Step 1.2
13 is between 0 and 1 inclusive, which meets the first property of the probability distribution.
13 is between 0 and 1 inclusive
Step 1.3
1 is between 0 and 1 inclusive, which meets the first property of the probability distribution.
1 is between 0 and 1 inclusive
Step 1.4
3 is not less than or equal to 1, which doesn't meet the first property of the probability distribution.
3 is not less than or equal to 1
Step 1.5
9 is not less than or equal to 1, which doesn't meet the first property of the probability distribution.
9 is not less than or equal to 1
Step 1.6
27 is not less than or equal to 1, which doesn't meet the first property of the probability distribution.
27 is not less than or equal to 1
Step 1.7
The probability P(x) does not fall between 0 and 1 inclusive for all x values, which does not meet the first property of the probability distribution.
The table does not satisfy the two properties of a probability distribution
The table does not satisfy the two properties of a probability distribution
Step 2
The table does not satisfy the two properties of a probability distribution, which means that the standard deviation can't be found using the given table.
Can't find the standard deviation
 [x2  12  π  xdx ]