Standard normal distribution Z ~ N(0,1): Mean=0, SD=1. Z-table gives cumulative probability P(Z ≤ z). Use for: Standardizing normal variables, hypothesis testing, confidence intervals. Finding probabilities: (1) P(Z ≤ 1.5) = 0.9332 (direct from table); (2) P(Z > 1.5) = 1 - 0.9332 = 0.0668; (3) P(-1 < Z < 1) = 0.8413 - 0.1587 = 0.6826. Critical values: 90% → ±1.645; 95% → ±1.96; 99% → ±2.576. Standardizing: Z = (X - μ)/σ. Example: IQ ~ N(100, 15). P(IQ < 115) = P(Z < 1) = 0.8413. Exam tip: Memorize critical values. Practice Z-table lookups. Understand reverse lookup (percentile to Z).