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resonance
10-10-2008, 03:45 AM
the formula =TDIST(ABS(X10),18,2) gives the p-value.
How does it do this? I know there's the degrees of freedom, but i have no idea what that is all about. HELP!

Thanks in advance!
JohnM
10-10-2008, 05:49 AM
The p-value is the probability of obtaining the t statistic (or larger) if the null hypothesis is true.
vinux
10-10-2008, 08:44 AM
the formula =TDIST(ABS(X10),18,2) gives the p-value.
How does it do this? I know there's the degrees of freedom, but i have no idea what that is all about. HELP!

Thanks in advance!


I guess you need the following.

X10 is the t-statistic value.
and
Pvalue = TDIST(ABS(X10),18,2) = P[ T<-X10 or T >X10 ]

where T follows Student's T distribution with 18 df