AlgèbreFacile
Math Learning PlatformStatistics — Cégep Level
Advanced
📚 statistiques
📖 About this lesson
Random variables, probability distributions and fundamental theorems
Lesson Content
Statistics — Cégep
Random Variables
E(X) = Σxᵢ·P(X=xᵢ) Var(X) = E(X²) - [E(X)]²
Normal Distribution
📋 Important Rule
Z = (X - μ) / σ 68-95-99.7 rule
Binomial Distribution
X~B(n,p): P(X=k) = C(n,k)·pᵏ·(1-p)ⁿ⁻ᵏ E(X)=np, Var(X)=np(1-p)
Practical Examples
1
Example 1
📋 Problem
X a E(X)=3 et E(X²)=13. Trouver Var(X) et σ.
✅ Solution
Var(X)=4, σ=2
💡 Explanation
Var = E(X²) - [E(X)]² = 13 - 9 = 4. σ = √4 = 2
2
Example 2
📋 Problem
Z = (X-50)10. Si X=65, trouver Z.
✅ Solution
Z = 1.5
💡 Explanation
Z = (65-50)10 = 1510 = 1.5
Ready to Practice? 💪
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