function [] = chap_5_prob_22()
% 
% Written by:
% -- 
% John L. Weatherwax                2007-04-02
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

% part a: 
zr = (0.905 - 0.9)/0.003;
zl = (0.895 - 0.9)/0.003;
p_acceptable = normcdf( zr ) - normcdf( zl );
p_defective = 1 - p_acceptable

% part b: 
sigma = -0.005/norminv(0.005)