FAQ/pvalues - CBU statistics Wiki

You can upload content for the page named below. If you change the page name, you can also upload content for another page. If the page name is empty, we derive the page name from the file name.

File to load page content from
Page name
Comment
In thi sntence, what word is mad fro the mising letters?

location: FAQ / pvalues

## Obtaining p-values in SPSS

The SPSS syntax below gives p-values for four distributions. These can also be done using a spreadsheet.

[CUT AND PASTE INTO A SPSS SYNTAX WINDOW, SELECT ALL AND RUN; AMEND DATA INPUT AS REQUIRED]

```* gives p-values for z, t, F and chi-square distributions
*
*
* example data set given below
*
* enter your own data in 4 columns as follows:
*
* distribution type: t=T distribution; z=Standard Normal; f=F distribution;
* c= chi-square distribution,
*
* critical value (cv),
*
* degrees of freedom (df, for the t,F and chi-square distributions),
*
* second degree of freedom (for F distribution only)
*
* non-applicable parameters should be denoted by a full stop (.)
*

set errors=none.
data list free
/ type (a1)  cv (f10.5) df (f10.5) df2 (f10.5).

begin data
t -1.645 5 .
z 2.58 . .
f 5 10 34
c 3.84 1 .
end data.

define !pvalt ( !pos !charend('/')
/ !pos !tokens(1)).
compute pout=2*(1-cdf.t(abs(!1),!2))*(type='t').
compute cv=!1.
compute df=!2.
!enddefine.

define !pvalz ( !pos !charend('/')).
compute pout=pout+2*(1-cdfnorm(abs(!1)))*(type='z').
!enddefine.

define !pvalf ( !pos !charend('/')
/ !pos !tokens(1)
/ !pos !tokens(1) ).
compute pout=pout+(1-cdf.f(!1,!2,!3))*(type='f').
!enddefine.

define !pvalc ( !pos !charend('/')
/ !pos !tokens(1)).
compute pout=pout+(1-cdf.chisq(!1,!2))*(type='c').
!enddefine.

define !pval (!pos !tokens(1)
/ !pos !charend('/')
/ !pos !tokens(1)
/ !pos !tokens(1)).
!if (!1 !eq 't') !then.
use all.
!pvalt  !2/ !3.
!ifend.
!if (!1 !eq 'z') !then.
use all.
!pvalz   !2/ .
!ifend.
!if (!1 !eq 'f') !then.
use all.
!pvalf  !2/ !3 !4.
!ifend.
!if (!1 !eq 'c') !then.
use all.
!pvalc  !2/ !3.
!ifend.
!enddefine.

!pvalt  cv/ df.
!pvalz  cv/ .
!pvalf  cv/ df df2.
!pvalc  cv/ df .

formats type (a1) cv df df2 pout (f11.8).
variable labels type 'Distribution' /cv 'Critical Value' /df 'df' /df2 'df2 for F' / pout '2-sided p-value'.
report format=list automatic align(center)
/variables=type cv df df2 pout
/title "Two-sided P-values for z, t, F and chi-square critical values".```