✅ Statistics & Probability Cheatsheet 📚🧠 📌 Descriptive Statistics: ⦁ Mean = (Σx) / n ⦁ Median = Middle value ⦁ Mode = Most frequent value ⦁ Variance (σ²) = Σ(x - μ)² / n ⦁ Std Dev (σ) = √Variance ⦁ Range = Max - Min ⦁ IQR = Q3 - Q1 📌 Probability Basics: ⦁ P(A) = Outcomes A / Total Outcomes ⦁ P(A ∩ B) = P(A) × P(B) (if independent) ⦁ P(A ∪ B) = P(A) + P(B) - P(A ∩ B) ⦁ Conditional: P(A|B) = P(A ∩ B) / P(B) ⦁ Bayes’ Theorem: P(A|B) = [P(B|A) × P(A)] / P(B) 📌 Common Distributions: ⦁ Binomial (fixed trials) ⦁ Normal (bell curve) ⦁ Poisson (rare events over time) ⦁ Uniform (equal probability) 📌 Inferential Stats: ⦁ Z-score = (x - μ) / σ ⦁ Central Limit Theorem: sampling dist ≈ Normal ⦁ Confidence Interval: CI = x ± z*(σ/√n) 📌 Hypothesis Testing: ⦁ H₀ = No effect; H₁ = Effect present ⦁ p-value < α → Reject H₀ ⦁ Tests: t-test (small samples), z-test (known σ), chi-square (categorical data) 📌 Correlation: ⦁ Pearson: linear relation (–1 to 1) ⦁ Spearman: rank-based correlation 🧪 Tools to Practice: Python packages: scipy.stats, statsmodels, pandas Visualization: seaborn, matplotlib 💡 Quick tip: Use these formulas to crush interviews and build solid ML foundations! 💬 Tap ❤️ for more
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