Harmonic Series Partial Sum H_n Calculator
Compute the n-th partial sum of the harmonic series Hₙ = Σₖ₌₁ⁿ 1/k. Also reports the Euler-Mascheroni approximation Hₙ ≈...
Compute the n-th partial sum of the harmonic series Hₙ = Σₖ₌₁ⁿ 1/k. Also reports the Euler-Mascheroni approximation Hₙ ≈...
Compute Hedges' g — Cohen's d adjusted for small-sample bias — from the mean difference, pooled SD, and total degrees of...
Compute the coefficient of determination R² from a Pearson correlation r: R² = r². R² × 100 % is the share of variance i...
Compute Cohen's d effect size = (M₁ − M₂) / SD_pooled, with rule-of-thumb interpretation (0.2 small, 0.5 medium, 0.8 lar...
Compute the geometric mean of a list of positive numbers — useful for averaging growth rates and ratios.
Perform one Newton-Raphson iteration to refine an estimate of a root: x_{new} = x − f(x) / f'(x), given the current esti...
Estimates plasma osmolality using: Posm = 2·Na + Glucose/18 + BUN/2.8 (all in mg/dL), or 2·Na + glucose_mmol + bun_mmol....
Calculates Macaulay duration and modified duration of a bond from coupon, yield, face value, and years to maturity.
Calculates SNR in dB from signal and noise power levels: SNR_dB = 10·log₁₀(P_s/P_n). Converts between linear SNR and dB....
Fit an ordinary least-squares regression line y = m·x + b directly from the standard running sums Σx, Σy, Σxy, Σx², and...
Compute the straight-line distance between two points (x₁, y₁) and (x₂, y₂) in the plane, plus the slope of the line thr...
Calculate your exact age in years, months, weeks, and days from a date of birth and a reference date.
Every "X% of Y" problem, every "what percent of", every percent-change question — written out the way you'd actually say them.
Standard deviation is "average distance from the average". That one sentence covers 90% of everything you ever need to remember about it.