Try this spreadsheet in Excel 2003. It uses the TINV function.
T Score from inverse confidence and degrees of freedom. Uses two tailed
probabilities.
95% 0.05
97% 0.03
99% 0.01
Sample size 10
degrees of freedom 9
tscore 95% 2.262
tscore 97% 2.574 <== This is an impossible value.
tscore 99% 3.250 It must be between 2.62 & 3.25

There appears to be a serious bug in the TINV function. The content of the
tscore column C cells is: =TINV(C5,$C$8)
Try it. This doesn't work correctly. MS needs to fix it pronto. Hard to
notify them.

The t values look correct to me looking at other statistical tables. Are
you sure you are not misreading the 2.262 as 2.62. Obviously the value
in the middle has to lie between 95% and 99% but I suspect you have
misread the lower value!

Regards

Dav


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Dav
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Yes, I misread it. Should have quit earlier doing my verifications for
each step. Had to do this for project up against SPSS. Glad it's my
mistake. Good example of negative productivity.


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BHanl
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Excel 2000 provides 6-figure accuracy for the first two and 5-figure accuracy
for the third.

Excel 2003 provides 8-figure accuracy for the first and 9-figure accuracy
for the last two.

Jerry

"BHanl" wrote:

Try this spreadsheet in Excel 2003. It uses the TINV function.
T Score from inverse confidence and degrees of freedom. Uses two tailed
probabilities.
95% 0.05
97% 0.03
99% 0.01
Sample size 10
degrees of freedom 9
tscore 95% 2.262
tscore 97% 2.574 <== This is an impossible value.
tscore 99% 3.250 It must be between 2.62 & 3.25

There appears to be a serious bug in the TINV function. The content of the
tscore column C cells is: =TINV(C5,$C$8)
Try it. This doesn't work correctly. MS needs to fix it pronto. Hard to
notify them.