I want to calculate the stdev of (colA - colB) in VBA code without
creating a new column. My attempted code below gives me a type
mismatch. Does anyone know how I would do it?

Public Sub calcStdev()

Dim myRangeAct As Range
Dim myRangeMod As Range

Set myRangeAct = Range(Cells(1, 1), Cells(100, 1))
Set myRangeMod = Range(Cells(1, 2), Cells(100, 2))

Debug.Print Application.WorksheetFunction.StDevP(myRangeAct)
Debug.Print Application.WorksheetFunction.StDevP(myRangeMod)

'GET TYPE MISMATCH
Debug.Print Application.WorksheetFunction.StDevP(myRangeAct -
myRangeMod)

End Sub

Thanks