Math Problem Statement

The Incorrect answer: Variable of a probability distribution is given by the formula . (E[(x-\mu _{x})^{2}\cdot P(x)])

Solution

It seems like you're trying to describe the variance of a probability distribution, but there are some details missing in the formula you've written. Let me clarify it.

The variance σ2\sigma^2 of a random variable XX in a probability distribution is given by:

Var(X)=E[(XμX)2]=(xμX)2P(x)\text{Var}(X) = E[(X - \mu_X)^2] = \sum (x - \mu_X)^2 \cdot P(x)

Where:

  • XX is the random variable.
  • μX\mu_X is the expected value (or mean) of the distribution, μX=E[X]\mu_X = E[X].
  • P(x)P(x) is the probability of each value xx.
  • E[(XμX)2]E[(X - \mu_X)^2] represents the expected value of the squared deviation from the mean.

In the corrected form, this formula expresses the variance of a discrete probability distribution, measuring how much the values of XX deviate from the mean μX\mu_X, weighted by their probabilities.

Would you like more details or have any other questions?


Here are five related questions to explore further:

  1. How do you calculate the mean μX\mu_X of a probability distribution?
  2. What is the relationship between variance and standard deviation?
  3. How does the formula for variance differ in continuous vs. discrete distributions?
  4. Can you compute the variance for a specific probability distribution example?
  5. What is the interpretation of variance in terms of data spread?

Tip: Variance is always non-negative because it involves squaring deviations, making the smallest possible value zero (when all outcomes are the same).

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Math Problem Analysis

Mathematical Concepts

Statistics
Probability
Variance

Formulas

Variance formula: Var(X) = E[(X - μ_X)^2] = Σ (x - μ_X)^2 · P(x)

Theorems

Law of Total Variance
Expected Value Theorem

Suitable Grade Level

College Level / Advanced High School