How this calculation works
A plain average would give the small group and large group equal weight. Combining the actual counts gives each observation equal weight.
THE FORMULA
100 × (s₁ + s₂)/(n₁ + n₂)A worked example
8 out of 10 and 30 out of 50 combine to 38 out of 60, about 63.33%.
Good to know
Use disjoint groups with comparable definitions of success.
Reference: OpenStax Prealgebra (opens in a new tab) ↗
Read the result
Pool two groups by adding counts so group sizes determine their weights.
The primary result is labeled “Combined percentage (%)”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
Use disjoint groups with comparable definitions of success.
For a related exercise, try the fraction calculator.
A few questions, answered
How can I check the default inputs by hand?
8 out of 10 and 30 out of 50 combine to 38 out of 60, about 63.33%.
Which rule does this calculator apply?
100 × (s₁ + s₂)/(n₁ + n₂)