First we define 21 inputs P and associated targets T: 

 >> P = -1:.1:1;
 >> T = (-.9602 -.5770 -.0729 -.3771 .6405 .6600 .4609 
        .1336 -.2013 -.4344 -.5000 -.3930 -.1647 .0988
        .3072 .3960 .3449 .1816 -.0312 -.2189 -.3201);

 Plot these 21 data points:
  
 >> plot(P,T,'+');