function P = spm_P_Bonf(Z,df,STAT,S,n)
% Returns the corrected P value using Bonferroni
% FORMAT P = spm_P_Bonf(Z,df,STAT,S,n)
%
% Z     - height {minium over n values}
% df    - [df{interest} df{error}]
% STAT  - Statisical feild
%		'Z' - Gaussian feild
%		'T' - T - feild
%		'X' - Chi squared feild
%		'F' - F - feild
% n     - number of conjoint SPMs
% S     - Voxel count
%
% P     - corrected   P value  - P(STAT > Z)
%
%___________________________________________________________________________
%
% spm_P_Bonf returns the p-value of Z corrected by the Bonferroni
% inequality. 
%
% If abs(n) > 1, a P-value for a minimum of n values of the statistic 
% is returned.  If n>0, the P-value assesses the conjunction null
% hypothesis of one or more of the null hypotheses being true.  If n<0,
% then the P-value assess the global null of all nulls being true. 
%
%___________________________________________________________________________
% @(#)spm_P_Bonf.m	2.3 Thomas Nichols 02/03/08
% $Id: spm_P_Bonf.m,v 1.1 2004/06/30 13:56:28 nichols Exp $ UM Biostat

if n>0
  Cnj_n = 1;       % Inf on Conjunction Null
else
  Cnj_n = abs(n);  % Inf on Global Null
end

if      STAT == 'Z'
  P = 1 - spm_Ncdf(Z);
elseif  STAT == 'T'
  P = 1 - spm_Tcdf(Z,df(2));
elseif  STAT == 'X'
  P = 1 - spm_Xcdf(Z,df(2));
elseif  STAT == 'F'
  P = 1 - spm_Fcdf(Z,df);
end

P = S*P.^Cnj_n;
P = min(P,1);