Math Problem Statement

Find E(X), E(X^2), and V(X) based on the given probability distribution table for X = {2, 3, 4, 5, 6} with probabilities {0.01, 0.25, 0.40, 0.30, 0.04}.

Solution

To solve part (a), we need to compute the expected value E(X)E(X), the expected value of X2X^2, and the variance V(X)V(X).

1. Expected Value E(X)E(X):

The expected value is given by the formula: E(X)=xfX(x)E(X) = \sum x \cdot f_X(x) where xx is the value of the random variable and fX(x)f_X(x) is the probability associated with xx.

Given dataTo solve part (a), we need to compute the expected value E(X)E(X), the expected value of X2X^2, and the variance V(X)V(X).

1. Expected Value E(X)E(X):

The expected value is given by the formula: E(X)=xfX(x)E(X) = \sum x \cdot f_X(x) where xx is the value of the random variable and fX(x)f_X(x) is the probability associated with xx.

Given

  • x=2,3,4,5,6x = 2, 3, 4, 5, 6
  • fX(x)=0.01,0.25,0.40,0.30,0.04f_X(x) = 0.01, 0.25, 0.40, 0.30, 0.04

We calculate E(X)E(X).

2. Expected Value of X2X^2 E(X2)E(X^2):

The expected value of X2X^2 is given by: E(X2)=x2fX(x)E(X^2) = \sum x^2 \cdot f_X(x) We will calculate this value by squaring xx and multiplying by fX(x)f_X(x).

3. Variance V(X)V(X):

Variance is calculated using: V(X)=E(X2)[E(X)]2V(X) = E(X^2) - [E(X)]^2 Once we compute E(X)E(X) and E(X2)E(X^2), we can find V(X)V(X).

Let me compute these now.The calculations yield the following results:

  1. E(X)=4.11E(X) = 4.11
  2. E(X2)=17.63E(X^2) = 17.63
  3. V(X)=0.738V(X) = 0.738 (rounded to three decimal places)

Would you like further clarification or additional details on any of these steps?

Here are some related questions to expand understanding:

  1. What is the interpretation of E(X)E(X) in probability distributions?
  2. How does E(X2)E(X^2) relate to higher moments in statistics?
  3. Why is variance V(X)V(X) important in understanding a random variable's spread?
  4. What is the significance of calculating the second moment in probability?
  5. How would the results change if the probabilities were altered?

Tip: To compute variance, always remember that it reflects the spread of data around the mean, while E(X)E(X) captures the central tendency.

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Math Problem Analysis

Mathematical Concepts

Expected Value
Variance
Probability Distribution
Discrete Random Variables

Formulas

E(X) = Σ [x * f_X(x)]
E(X^2) = Σ [x^2 * f_X(x)]
V(X) = E(X^2) - [E(X)]^2

Theorems

Expected Value Theorem
Variance Theorem

Suitable Grade Level

Grades 11-12 or College