x=2:16;
     y=[6.42 8.20 9.58 9.5 9.7 10 9.93 9.99 10.49 10.59 10.60 10.80 10.60 10.90 10.76];
     beta0=[8 2]';
     
[beta,r,J]=nlinfit(x',y','volum',beta0);

[YY,delta]=nlpredci('volum',x',beta,r ,J);
plot(x,y,'k+',x,YY,'r')