
1. Re: How do you get this formula for calculating tstatistics to work
swaroop.gantela May 1, 2018 4:06 PM (in response to Dennis Pong)Dennis,
I don't think I got the details right, but I think the gist of it should work:
([Avg2][Avg1])
/
(SQRT([VarP1]/[Count1]+[VarP2]/[Count2]))
These subparts are further defined in the workbook attached
in the Forum thread.
I made a mock dataset. Please adjust it to more match yours.
It looked like the values in Tableau were matching the rough
calculations I made in Excel on Sheet2 of the attached.
I wasn't sure what the delta was in the posted equation.

269085stat.xlsx 10.4 KB

269085stat.twbx 13.2 KB


3. Re: How do you get this formula for calculating tstatistics to work
swaroop.gantela May 1, 2018 8:05 PM (in response to Dennis Pong)1 of 1 people found this helpfulDennis,
These are deep waters.
Based on a cursory reading of
It looks like with a known pooled variance Sp, you could rearrange and get the ratio of S1 to S2.
In the tstat equation, you appear to have all the parts except S1 and S2,
and from the above equation you could substitute S2 with (some constant)*S1.
But it still feels like you would need to know at least one of the actual variances in order
to get a final number.
Hopefully others in the Forum can chime in.