Statistics · Calculator companion · By K Imports
Independent event probabilities: practical guide
This guide explains how to use the Count.ie independent event probabilities. Calculate intersections, unions and repeat-trial success chances. Follow the inputs, method and worked example below, then compare your own scenario.
Guide written .
Open the Independent event probabilities calculatorWhat to prepare
- Collect the underlying observations and state how they were sampled.
- Identify the population, sample size and relevant assumptions.
- Check whether observations, probabilities or measurements are independent where the method requires it.
Understand the inputs
The calculation method
Independent events: P(A and B)=ab, P(A or B)=a+b−ab; at least one A in n trials = 1−(1−a)^n.
Worked example
Illustrative inputs and their result.
Example inputs
- Chance of event A (%)
- 20
- Chance of event B (%)
- 30
- Independent trials of event A
- 10
Calculated example result
- Both Events Percent
- 6%
- At Least One AIn Trials Percent
- 89.2626%
How to interpret the result
A statistic summarises the supplied data; it does not repair biased sampling or establish causation. Uncertainty depends on the method's assumptions, not just the number of decimal places shown.
Compare equivalent datasets and report the sample size with the result. Where appropriate, test how an outlier or a different uncertainty assumption affects the conclusion.
Common mistakes to avoid
- Do not substitute population and sample definitions without checking the formula.
- Outliers, missing observations and selection bias can change the interpretation.
- A correlation or significance result is not proof of a causal relationship.
Assumptions and sources
Editable inputs are planning assumptions; check the method and result notes for scope.
If your case falls outside this scope, use a more suitable calculator or contact us about an unclear method.