ClueLuma

Cumulative variance calculator

Add the current signed residual to the previous cumulative total to reveal persistent performance changes.

CUSUMn=CUSUMn−1+Variancen\mathrm{CUSUM}_{n} = \mathrm{CUSUM}_{n-1} + \text{Variance}_{n}

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

energy unit
energy unit
energy unit

Worked example

Given

  • CUSUMn−1\mathrm{CUSUM}_{n-1} = -5,800 energy unit
  • Variancen\text{Variance}_{n} = -2,200 energy unit
CUSUMn=(−5800)+(−2200)=−8,000\mathrm{CUSUM}_{n} = \left(-5800\right) + \left(-2200\right) = -8{,}000

Symbols and units

SymbolMeaningUnit
CUSUMn\mathrm{CUSUM}_{n}cumulative signed variance through nenergy unit
CUSUMn−1\mathrm{CUSUM}_{n-1}prior cumulative varianceenergy unit
Variancen\text{Variance}_{n}current actual minus predictedenergy unit

Related calculators

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.