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X P(x)

0 0.1
1 0.05
2 0.1
3 0.75


Find the standard deviation of this probability distribution. Give your answer to at least 2 decimal places

User Dave White
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1 Answer

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Answer: To find the standard deviation of a probability distribution, we need to first calculate the mean or expected value of the distribution, which is given by:

E(X) = Σ [xi * P(xi)]

where xi is the ith outcome and P(xi) is its probability.

So, for the given distribution:

E(X) = (0 * 0.1) + (1 * 0.05) + (2 * 0.1) + (3 * 0.75) = 2.4

Next, we need to calculate the variance of the distribution, which is given by:

Var(X) = Σ [(xi - E(X))^2 * P(xi)]

So, for the given distribution:

Var(X) = (0 - 2.4)^2 * 0.1 + (1 - 2.4)^2 * 0.05 + (2 - 2.4)^2 * 0.1 + (3 - 2.4)^2 * 0.75 = 0.69

Finally, the standard deviation of the distribution is the square root of the variance:

SD(X) = sqrt(Var(X)) = sqrt(0.69) ≈ 0.83

Therefore, the standard deviation of this probability distribution is approximately 0.83, rounded to 2 decimal places.

Explanation:

User Pierlo Upitup
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