function coeff = prune_det_coeff_C45(CF)
% PRUNE_DET_COEFF determines the coeff value used in the C4.5 tree pruning
%	algorithm
%
%	coeff = prune_det_coeff_C45(CF)
%
%	CF: certainty factor passed 
%	  

% Val, Dev are from a normal distribution lookup-table

Val = [   0, 0.001, 0.005, 0.01, 0.05, 0.10, 0.20, 0.40, 1.00 ];
Dev = [ 100, 3.09,  2.58,  2.33, 1.65, 1.28, 0.84, 0.25, 0.00 ];

% determine coeff:

i = 1;

while (CF > Val(i))
	i = i + 1;
end % while

x = Dev(i-1) +((Dev(i) - Dev(i-1))*(CF - Val(i-1)))/(Val(i) - Val(i-1));
coeff = x * x;