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This guide covers the concepts of mean (expected value), variance, and standard deviation for discrete random variables. It explains how to calculate the mean using the formula µ = ΣxP(x), where each value is multiplied by its probability, and discusses the expected value using a lottery example with 1 ticket sold from 1500. Additionally, it provides formulas for variance (σ² = Σ(x - µ)²P(x)) and standard deviation (σ = √σ²). Learn through multiple examples how to apply these concepts effectively.
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4.1B – Probability Distribution • MEAN of discrete random variable: µ = ΣxP(x) • EACH x is multiplied by its probability and the products are added. • µ = EXPECTED VALUE of discrete random variables
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Example: Find the EXPECTED VALUE of your gain. • 1500 tickets are sold for $2 each for 4 prizes of $500, $250, $150, and $75. You buy 1 ticket. What is the expected value of your gain?
Standard Deviation • VARIANCE of discrete random variable σ² = Σ(x-µ)²P(x) OR σ² = [Σx²P(x)] - µ² • STANDARD DEVIATION of discrete random variable σ = √σ²
Example: Find Variance & Standard Deviation σ = √σ² = √1.616 = 1.27