Math & statistics
Normal distribution interval probability
Normal distribution interval probability with an explained formula, a worked example and checks for invalid or unsupported inputs.
Math & statistics — Page 2
Choose a tool. The method, example and assumptions are included.
Showing 25–48 of 72 tools
Math & statistics
Percentile with linear interpolation
Percentile with linear interpolation with an explained formula, a worked example and checks for invalid or unsupported inputs.
Math & statistics
Permutations
Permutations: n! ÷ (n−r)!; order matters
Math & statistics
Poisson event probability
Poisson event probability with an explained formula, a worked example and checks for invalid or unsupported inputs.
Math & statistics
Polynomial definite integral by Simpson’s rule
Polynomial definite integral by Simpson’s rule: Composite Simpson’s rule: h/3 × [f(a)+f(b)+4Σ odd interior samples+2Σ even interior samples], evaluating the entered polynomial with Horner’s method.
Math & statistics
Polynomial value and derivative
Polynomial value and derivative: Evaluate coefficients with Horner’s method.
Math & statistics
Powers and roots
Powers and roots: Raise the base to the supplied real exponent
Math & statistics
Prime factorization
Decompose a positive whole number into prime factors, exponents and the number of positive divisors.
Math & statistics
Quadratic roots
Quadratic roots: Solve ax² + bx + c = 0 using the discriminant; real roots only
Math & statistics
Range
Range: Maximum minus minimum
Math & statistics
Root mean square (RMS)
Root mean square (RMS) with an explained formula, a worked example and checks for invalid or unsupported inputs.
Math & statistics
Simple linear regression
Simple linear regression with an explained formula, a worked example and checks for invalid or unsupported inputs.
Math & statistics
Solve a linear equation system
Solve a linear equation system: Apply Gaussian elimination with partial pivoting to an n×(n+1) augmented matrix.
Math & statistics
Spearman rank correlation with ties
Spearman rank correlation with ties: Rank each series with average ranks for ties, then calculate Pearson correlation between the two rank series.
Math & statistics
Standard deviation
Standard deviation: Sum squared deviations from mean ÷ N (population) or N−1 (sample); take square root
Math & statistics
Survey sample size for a proportion
Plan a survey sample size for a proportion from a confidence level, absolute margin and optional population correction.
Math & statistics
Variance
Variance: Sum squared deviations from mean ÷ N (population) or N−1 (sample)
Math & statistics
Weighted average
Weighted average: Σ(value × weight) ÷ Σweights
Math & statistics
Weighted median
Weighted median with an explained formula, a worked example and checks for invalid or unsupported inputs.
Math & statistics
Welch two-sample t statistic and degrees of freedom
Welch two-sample t statistic and degrees of freedom: Set a = s₁²/n₁ and b = s₂²/n₂.
Math & statistics
Z-score standardization
Express an observation as the number of population standard deviations above or below the mean.
Math & statistics
Real nth root
Real nth root: Solve y^n = x over the real numbers.
Math & statistics
Exponential decay and remaining amount
Exponential decay and remaining amount: Remaining amount = initial amount × 2^(−elapsed time / half-life).
Math & statistics
Exponential growth doubling time
Exponential growth doubling time: Doubling time = ln(2) / ln(1 + growth/100), with a strictly positive growth rate.