Excel VBA: t-test for summary results

gistfile1.vb

Function ttest_from_sum(x As Range, y As Range, values As Range)

' Set up for dragging over names with lookup
' Change this to fit your needs

Set temp = values.Find(x.Value, LookIn:=xlValues)
avga = CDec(temp.Offset(1, 0).Value)
stda = CDec(temp.Offset(2, 0).Value)
numa = CDec(temp.Offset(3, 0).Value)

Set temp = values.Find(y.Value, LookIn:=xlValues)
avgb = CDec(temp.Offset(1, 0).Value)
stdb = CDec(temp.Offset(2, 0).Value)
numb = CDec(temp.Offset(3, 0).Value)

pooled_sd = Sqr(((stda * stda) / numa) + ((stdb * stdb) / numb))
t_stat = (avga - avgb) / pooled_sd

' Set up for two-tailed probability
t_prob = WorksheetFunction.TDist(Abs(t_stat), (numa + numb) - 2, 2)

ttest_from_sum = Round(t_prob,2)

End Function