- Fraction Calculator
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- Probability Calculator
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Password Combination CalculatorCalculate the total number of possible password combinations and entropy in bits from your character set size and password length.
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Probability of 3 Events CalculatorCalculate the probability of three independent events all occurring with P(A and B and C) = P(A)×P(B)×P(C). Also shows at-least-one and none.
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Relative Risk CalculatorCalculate relative risk (RR) from a 2x2 table. Enter exposed/unexposed counts with and without the outcome to get the risk ratio instantly.
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Coin Flip Probability CalculatorCalculate the probability of getting exactly k heads in n coin flips using the binomial formula. Supports fair and biased coins, plus cumulative odds.
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P-Hat CalculatorCalculate p-hat (sample proportion) instantly with p̂ = x / n. Enter successes and sample size to get the proportion, percentage, and complement.
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Permutation CalculatorCalculate permutations P(n,r) = n!/(n-r)! instantly. Find the number of ordered arrangements of r items chosen from n distinct items.
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Joint Probability CalculatorCalculate the joint probability P(A and B) of two independent events by multiplying their individual probabilities. Free, instant, with worked examples.
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False Positive Paradox CalculatorCalculate the true probability of disease after a positive test using Bayes' theorem. Enter prevalence, sensitivity and specificity to see the false positive paradox.
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Implied Probability CalculatorConvert decimal or American (moneyline) betting odds into implied probability. Free calculator showing the percentage chance behind any odds.
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Dice Probability CalculatorCalculate the probability of rolling a target sum with any number of dice and sides. Get favorable outcomes, total combinations, percentage and odds.
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Expected Value CalculatorCompute the expected value (mean) of a discrete random variable from outcome values and their probabilities using E(X) = Σ xᵢ·pᵢ. Free and instant.
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Dice Average CalculatorCalculate the average (expected) total when rolling any number of dice with any number of sides. Free dice average calculator with min/max totals.
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Combination CalculatorCalculate combinations C(n,r) = n!/(r!(n-r)!) instantly. Find how many ways to choose r items from n when order doesn't matter, plus permutations.
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Conditional Probability CalculatorCalculate conditional probability P(A|B) instantly. Enter P(A and B) and P(B) to find the probability of A given B, shown as a value and percentage.
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Bayes' Theorem CalculatorCalculate the posterior probability P(A|B) using Bayes' theorem from the prior, likelihood, and false-positive rate. Free, instant, with worked examples.
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Chebyshev's Theorem CalculatorUse Chebyshev's Theorem to find the minimum proportion of data within k standard deviations of the mean. Works for any distribution shape.
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Accuracy CalculatorCompute classification accuracy from a confusion matrix. Enter TP, TN, FP and FN to get accuracy as a percentage and ratio instantly.
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Chi-Squared Distribution Random Number GeneratorGenerate pseudo-random numbers drawn from a chi-squared distribution with any positive degrees of freedom v. Returns up to 1000 non-negative values plus theoretical mean, variance and SD.
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Diagnostic Test Accuracy CalculatorCompute sensitivity, specificity, false positive/negative rate, PPV, NPV and prevalence from a 2x2 diagnostic confusion matrix. Universal epidemiology tool.
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Gamma Distribution Random Number GeneratorGenerate pseudo-random numbers following a Gamma distribution with shape a and scale b. Uses the Marsaglia-Tsang method; reports sample mean and variance.
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Student's t-Distribution Random Number GeneratorGenerate pseudo-random numbers from a Student's t-distribution with your chosen degrees of freedom. Set the count (1-1000) and get instant t-distributed samples.
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Log-Normal Distribution Random Number GeneratorGenerate pseudo-random numbers from a log-normal distribution using the Box-Muller transform. Set mu, sigma and count; see theoretical mean, median and variance.
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Normal Distribution Random Number Generator (Box-Muller Method)Generate pseudo-random numbers from a normal (Gaussian) distribution with your chosen mean and standard deviation using the Box-Muller transform.
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Levy Distribution CalculatorCompute the Levy distribution PDF f(x), lower cumulative probability P(x) and upper cumulative probability Q(x) from location mu and scale c.
