Calculate permutations, combinations, binomial probability density, normal distribution Z-scores, and sample size margins with interactive graphs.
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How to Use Probability Calculator
Select the probability module: Combinations/Permutations, Binomial distribution, or Normal distribution.
Enter the inputs (number of trials, success probabilities, bounds).
Review the computed outcome and mathematical probability formulas.
Examine the interactive distribution curve plot showing standard deviations and z-scores.
Statistical Probability Slabs
Probability distributions describe the likelihood of outcomes in random events. The binomial distribution represents discrete scenarios (e.g. coin flips), while the normal distribution describes continuous natural variations (e.g. component tolerances, test marks).
Frequently Asked Questions
What is the difference between permutation and combination?
Permutations account for the order of selection (e.g. arranging medals), while combinations ignore the order (e.g. selecting a committee).
What does a Z-score represent?
A Z-score indicates how many standard deviations an observation is from the mean of a normal distribution. It normalizes datasets to determine probability densities.