Mann Kendall Trend Test Calculator
Calculate a tie-corrected, continuity-corrected two-sided Mann–Kendall trend statistic.
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
Compare every ordered pair and adjust the null variance for tied observed values.
S=Σsign(xj−xi); Var(S)=[n(n−1)(2n+5)−Σt(t−1)(2t+5)]/18
Worked example
A strictly increasing five-point series has S10 and tie-free variance50/3.
Assumptions and input details
Independent observations under the null, ordinary asymptotic normal approximation and unit continuity correction. No seasonal adjustment or serial-correlation correction; short or autocorrelated series can make p-values unreliable.
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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