function [ci] = bootstrp_sci(nboot, bootfun, data, alpha)
% BOOTSTRP_SCI - returns the bootstrap standard confidence interval with a probability of type I error of alpha
%   
% Input: 
%   data: is a one dimensional matrix (i.e. a vector of lenth ndata) 
%   alpha: the probability we make a type I error (reject H_0 when in fact it is true)
% Output: 
%   ci: the standard confidence interval for bootfun
% 
% Written by:
% -- 
% John L. Weatherwax                2008-02-20
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

if( nargin<4 ) alpha=0.05; end

% get the bootstrap samples of the function bootfun: 
[bootstat] = bootstrp( nboot, bootfun, data ); 
% get the empirical quantiles of our bootfun (from the bootstrap estimates) 
ci = quantile( bootstat, [ 0.5*alpha, 1-0.5*alpha ] );