A TI-84 style calculator for AP Statistics. Switch between three modes using the tabs on the screen.
Calculates the area under the normal curve between two values. Gives P(lower < X < upper).
Use -999 for negative infinity and 999 for positive infinity.
Example: normalcdf(-999, 1.5, 0, 1) = 0.9332 → P(Z < 1.5)
Given a left-tail area (probability), finds the corresponding cutoff value.
Example: invNorm(0.95, 0, 1) = 1.6449
Calculates z = (x − μ) / σ and gives the corresponding tail probabilities.
Example: x = 75, μ = 70, σ = 5 → z = 1.00
• P(Z < 1.645) ≈ 0.95 → 90% confidence critical value
• P(Z < 1.960) ≈ 0.975 → 95% confidence critical value
• P(Z < 2.576) ≈ 0.995 → 99% confidence critical value
• P(Z < -1.645) ≈ 0.05 (left tail α = 0.05)