Cochran Armitage Trend Calculator
Calculate a signed asymptotic trend statistic for binary outcomes across groups with entered numeric scores.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Pool the success rate and test its association with the prespecified quantitative ordering using a normal approximation.
Z=Σ wi(xi−ni p)/√(p(1−p)Σni(wi−weighted mean score)²)
Worked example
Counts 1,3,6 out of 10 each at scores 0,1,2 give positive Z≈2.37170825. Reversing scores changes only the sign.
Assumptions and input details
Independent groups, binomial counts and prespecified scores. Uses the asymptotic uncorrected trend-score variance, not an exact conditional test. Sparse groups and data-chosen scores limit inference; no causal dose response or multiplicity correction.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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