Math Problem Statement

. Find the mean of the probability distribution of a random variable X which can take only the values 1, 2, and 3, given that P(1) = 10/33 P(2) = 1/3 P(3) = 12/33

Solution

To find the mean (or expected value) of the probability distribution of the random variable XX, you use the formula:

μ=E(X)=ixiP(xi)\mu = E(X) = \sum_{i} x_i \cdot P(x_i)

Here, XX can take the values 11, 22, and 33, with the corresponding probabilities P(1)=1033P(1) = \frac{10}{33}, P(2)=13P(2) = \frac{1}{3}, and P(3)=1233P(3) = \frac{12}{33}.

Step 1: Write down the values and probabilities.

  • x1=1x_1 = 1, P(x1)=1033P(x_1) = \frac{10}{33}
  • x2=2x_2 = 2, P(x2)=13P(x_2) = \frac{1}{3}
  • x3=3x_3 = 3, P(x3)=1233P(x_3) = \frac{12}{33}

Step 2: Calculate the mean.

μ=11033+213+31233\mu = 1 \cdot \frac{10}{33} + 2 \cdot \frac{1}{3} + 3 \cdot \frac{12}{33}

Step 3: Simplify the expression.

Let's simplify each term: μ=1033+213+31233\mu = \frac{10}{33} + 2 \cdot \frac{1}{3} + 3 \cdot \frac{12}{33}

Convert the fraction 13\frac{1}{3} to a fraction with a denominator of 33: 213=21133=22332 \cdot \frac{1}{3} = 2 \cdot \frac{11}{33} = \frac{22}{33}

Now, substitute and simplify: μ=1033+2233+3633=10+22+3633=6833\mu = \frac{10}{33} + \frac{22}{33} + \frac{36}{33} = \frac{10 + 22 + 36}{33} = \frac{68}{33}

So, the mean of the probability distribution is: μ=68332.06\mu = \frac{68}{33} \approx 2.06

Would you like more details or have any questions?

Here are five related questions:

  1. What is the variance of the probability distribution?
  2. How do you interpret the expected value in the context of probability distributions?
  3. What is the probability that XX takes a value greater than the mean?
  4. How would the mean change if P(2)P(2) increased?
  5. Can the mean be outside the range of possible values for XX?

Tip: The mean (or expected value) provides a measure of the central tendency of a probability distribution, representing the average outcome if the experiment is repeated many times.

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Math Problem Analysis

Mathematical Concepts

Probability Theory
Expected Value
Probability Distribution

Formulas

Expected Value formula: E(X) = \sum_{i} x_i \cdot P(x_i)

Theorems

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Suitable Grade Level

Advanced