Descriptive statistics, correlation, probability distributions, confidence intervals, t-tests, A/B tests, sample sizes, combinatorics and number theory.
payments ON MAINNET (real money) · 10 live endpoints
| Endpoint | Price | What it answers |
|---|---|---|
GET /ab-test | $0.02 | A/B conversion test: rates, relative lift, two-proportion z-test p-value, confidence interval and a significance verdict. |
GET /combinatorics | $0.02 | Exact counts: factorial, combinations, permutations, with repetition, derangements and Catalan numbers, as big integers. |
GET /confidence-interval | $0.02 | Confidence interval for a mean (t interval from a list) or a proportion (Wilson and Wald from successes and trials). |
GET /correlation | $0.02 | Pearson and Spearman correlation of two lists with p-values, plus the least-squares line, R squared and an optional prediction. |
GET /distribution | $0.02 | Probability density or mass, cumulative probability and quantiles for normal, binomial, Poisson and Student t distributions. |
GET /gcd-lcm | $0.02 | Greatest common divisor, least common multiple, Bezout coefficients and modular inverse for integers of any size. |
GET /prime-factor | $0.02 | Primality test and prime factorization of integers up to 10^19, with divisor count, divisor sum, Euler totient and number type. |
GET /sample-size | $0.02 | Required sample size for a survey (margin of error, optional finite population) or an A/B test (baseline, lift, power). |
GET /stats-describe | $0.02 | Descriptive statistics for a list of numbers: mean, median, mode, spread, quartiles, outliers, skewness and kurtosis. |
GET /t-test | $0.02 | Welch two-sample or one-sample t-test: t statistic, degrees of freedom, p-value, confidence interval and Cohen's d. |
GET /catalog returns this list as JSON. Activity hub · uptime.
All results are computed locally with standard numerical methods and provided as is; numeric answers are accurate to about 10 significant digits for ordinary inputs. Statistical tests rest on assumptions (independence, rough normality, adequate sample size) that this service cannot verify, and a significant result is not proof of cause. Not professional statistical, medical or financial advice. Inputs travel in the query string, so keep data lists short and never send personal data. Every paid response carries a disclaimer field.