software

My question is how can I calculate a p-value for a negative t-value?

In several tests the t-test value is negative and I cannot use the standard
TDIST(x,df,1) function. Is it correct to calculate the p-value of negative
t-values as:
1 - absolute(P[x])?

If the above is correct, is this the correct adaption to the TDIST function:
=IF(xgt;0,TDIST(x,deg_freedom,tails),(1-(TDIST(ABS(x),deg_freedom,tails))))

--
Mahalo for your help,
Camper

Camper -

Here are some excerpts from my book, quot;Data Analysis Using Microsoft Excel:
Updated for Office XPquot;:

Left-Tail Test
p-value =IF(tlt;0,TDIST(ABS(t),df,1),1-TDIST(t,df,1))

Right-Tail Test
p-value =IF(tgt;0,TDIST(t,df,1),1-TDIST(ABS(t),df,1))

Two-Tail Test
p-value =TDIST(ABS(t),df,2)

- Mike
www.mikemiddleton.com

quot;Camperquot; gt; wrote in message
...
gt; My question is how can I calculate a p-value for a negative t-value?
gt;
gt; In several tests the t-test value is negative and I cannot use the
gt; standard
gt; TDIST(x,df,1) function. Is it correct to calculate the p-value of negative
gt; t-values as:
gt; 1 - absolute(P[x])?
gt;
gt; If the above is correct, is this the correct adaption to the TDIST
gt; function:
gt; =IF(xgt;0,TDIST(x,deg_freedom,tails),(1-(TDIST(ABS(x),deg_freedom,tails))))
gt;
gt; --
gt; Mahalo for your help,
gt; Camper
Aloha Mike,

That answers my question and is exactly what I needed. Mahalo for the
reference to the book. I will have to track down a copy for my
library/reference collection.
--
Mahalo for your help,
Camperquot;Mike Middletonquot; wrote:

gt; Camper -
gt;
gt; Here are some excerpts from my book, quot;Data Analysis Using Microsoft Excel:
gt; Updated for Office XPquot;:
gt;
gt; Left-Tail Test
gt; p-value =IF(tlt;0,TDIST(ABS(t),df,1),1-TDIST(t,df,1))
gt;
gt; Right-Tail Test
gt; p-value =IF(tgt;0,TDIST(t,df,1),1-TDIST(ABS(t),df,1))
gt;
gt; Two-Tail Test
gt; p-value =TDIST(ABS(t),df,2)
gt;
gt; - Mike
gt; www.mikemiddleton.com
gt;
gt; quot;Camperquot; gt; wrote in message
gt; ...
gt; gt; My question is how can I calculate a p-value for a negative t-value?
gt; gt;
gt; gt; In several tests the t-test value is negative and I cannot use the
gt; gt; standard
gt; gt; TDIST(x,df,1) function. Is it correct to calculate the p-value of negative
gt; gt; t-values as:
gt; gt; 1 - absolute(P[x])?
gt; gt;
gt; gt; If the above is correct, is this the correct adaption to the TDIST
gt; gt; function:
gt; gt; =IF(xgt;0,TDIST(x,deg_freedom,tails),(1-(TDIST(ABS(x),deg_freedom,tails))))
gt; gt;
gt; gt; --
gt; gt; Mahalo for your help,
gt; gt; Camper
gt;
gt;
gt;