TTEST function give wrong answer!

[Bruce Backman]

Hi,
Has anyone else found any inconsistencies between what
Excel gives as a test statistic versus the value derived
from manual calculation? In my case, TTEST gave a value of
0.08 when the manual calculation (using the formula given
in the Excel Help Files) gave 1.81 . It was the difference
between statistical significance...frustrating
Bruce

 

[Mike Middleton]

Bruce Backman -

Has anyone else found any inconsistencies between what Excel gives as a

test statistic versus the value derived from manual calculation? In my case,
TTEST gave a value of 0.08 when the manual calculation (using the formula
given in the Excel Help Files) gave 1.81 . It was the difference between
statistical significance...frustrating <

Huh?

The formula in the Help files is for calculating the test statistic t, e.g.,
t = 1.81.

The TTEST worksheet function returns the associated one-tail or two-tail
probability value, e.g., one-tail P(T>t) = P(T>1.81) = 0.08, or two-tail
P(T<-t)+P(T>t).

- Mike Middleton, www.usfca.edu/~middleton

P.S. If you need more examples, consult any statistics book that uses Excel,
e.g., Middleton's Data Analysis Using Microsoft Excel: Updated for Office
XP.

 

[Bruce Backman]

Thanks Mike! Much appreciated.

-----Original Message-----
Bruce Backman -
Excel gives as a
test statistic versus the value derived from manual calculation? In my case,
TTEST gave a value of 0.08 when the manual calculation (using the formula
given in the Excel Help Files) gave 1.81 . It was the difference between
statistical significance...frustrating <

Huh?

The formula in the Help files is for calculating the test statistic t, e.g.,
t = 1.81.

The TTEST worksheet function returns the associated one- tail or two-tail
probability value, e.g., one-tail P(T>t) = P(T>1.81) = 0.08, or two-tail
P(T<-t)+P(T>t).

- Mike Middleton, www.usfca.edu/~middleton

P.S. If you need more examples, consult any statistics book that uses Excel,
e.g., Middleton's Data Analysis Using Microsoft Excel: Updated for Office
XP.


.