Hypergeometric Calculator

Form

Results

Chance to draw 4 or more of the wanted card

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Chance to draw exactly 4 of the wanted card

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Chance to draw 4 or less of the wanted card

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Chance to draw 0 of the wanted card

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What is Hypergeometric?

The hypergeometric distribution models a fixed-size draw without replacement.

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How to Use This Calculator

  1. Enter or select Population Size (N), Sample Size (n), Successes in population (K), Successes in Sample (k).
  2. Check the unit beside each measurement. For a percentage or rate, use the scale and time period stated in the form.
  3. Choose Calculate, then compare the output with the formula and example below. If you change a value or option, calculate again to update the result.
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Formula Used

P(X=k)=C(K,k)C(N−K,n−k)/C(N,n)
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Variables Explained

InputWhat it means
Population Size (N)Total number of eligible members in the population being studied.
Sample Size (n)Number of observations or responses in the sample, rather than the population size.
Successes in population (K)Total number of eligible members in the population being studied.
Successes in Sample (k)Use the measured or stated value for this item, with the unit or category shown beside the field.
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Worked Example

From 10 objects with 4 successes, drawing 2 gives P(both successes)=6/45≈0.1333.

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Why Use This Calculator?

Calculate draw probabilities when selections are made without replacement.

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Common Mistakes

    • Sampling without replacement makes draws dependent; do not substitute a binomial model without checking.
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Frequently Asked Questions

Does a calculated statistic prove a conclusion?

A statistic describes the supplied data under stated assumptions. Sampling design, missing observations and the suitability of the model still determine what can reasonably be concluded.

Should I include every observation?

Use the observations required by your study design and state any exclusion rule. Removing values only because they change the answer can bias the analysis.

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Sources & References