ExcelBanter - student's t table

Aurélie -

Refer to TDIST in Excel's built-in Help.

For more details, here is an excerpt from my book, "Data Analysis Using
Microsoft Excel: Updated for Office XP."

TDIST returns probability in the tail(s) of the density function, with
syntax
TDIST(x,degrees_freedom,tails),
where x is the numerical value at which to evaluate the distribution,
degrees_freedom is an integer indicating the number of degrees of freedom,
and tails specifies the number of distribution tails to return. If tails =
1, TDIST returns a right-tail probability, and if tails = 2, TDIST returns
twice the right-tail probability. The value of x must not be negative.
For example, the left-tail probability, P(t <= Max), is computed using the
formula
=IF(Max<0,TDIST(ABS(Max),df,1),1-TDIST(Max,df,1)),
where df is an integer for degrees of freedom and Max is a value or a
reference to a value. Similarly, the right-tail probability, P(t = Min), is
computed using
=IF(Min<0,1-TDIST(ABS(Min),df,1),TDIST(Min,df,1)).
The probability in a symmetric range around zero, P(-Value <= t <= Value),
is computed using
=1-TDIST(Value,df,2)
where Value is a positive number or a reference to a positive number.
TINV returns the inverse of the Student's t distribution, with syntax
TINV(probability,degrees_freedom),
where probability is twice the right-tail probability or the probability in
the sum of two tails, and degrees_freedom is the number of degrees of
freedom. TINV always returns a positive value of t.
The value, Max, corresponding to the cumulative left-tail probability, Prob,
such that
P(t <= Max) = Prob, is computed using
=IF(Prob<0.5,-TINV(2*Prob,df),TINV(2*(1-Prob),df)),
where df is an integer for degrees of freedom, and Prob is a value between
zero and one or a reference to a value.

- Mike
www.mikemiddleton.com

"Aurélie" wrote in message
...
I am used to generating t table in mathcad but I can'y find any t table in
excel... I would like to ude it for a variable value : depending on the
sample size ( it's in order to fit S-N curve for different materials)
Thank you for your help,

PS : Please, excuse me for my English because I am French