Hi Hugh,
I am not sure about the Z matrix, and I replaced 0 in the empty positions, and of course, you can change it. For instance, at the fourth row of matrix Z, I assumed that all the elements are zero except the fourth one. In the end, I added a part to plot the data and visualise it.
I hope it helps!
x=[25 40 50 65 70 75 89 107 132 158 172 194 232 250 275 310 348];
y=[1300 2600 3750 4500 5800 7100 8400 9700 11000 12300 13000];
Z=[ 0.096234615 0.239117308 0.385056 0.487474444 0.675744828 0.874833803 1.082447024 1.296634021 1.516019091 1.739652846 1.861441923;
1.511103846 1.893471154 2.130796 2.259105556 2.44990431 2.612664789 2.755516071 2.883509278 2.999915455 3.106855691 3.161123462;
1.522857692 1.911469231 2.153716 2.284784444 2.480200862 2.647233099 2.794057143 2.925745876 3.045581818 3.155847967 3.211885385;
0 0 0 3.2499565 0 0 0 0 0 0 0;
1.536080769 1.932405769 2.180456 2.315132222 2.515931034 2.687854225 2.839305952 2.975464948 3.099495909 3.213846748 3.271903462;
1.538284615 1.936078846 2.18504 2.320225556 2.522023276 2.694714085 2.847036905 2.983931959 3.108698636 3.223707317 3.282188077;
2.761419231 2.986578846 3.182314667 3.308544444 3.524443966 3.736471127 3.944945833 4.149721134 4.350806364 0 0 ;
3.320461538 3.590432692 3.826112 3.977681111 4.237236207 4.492266197 4.742825595 4.989038144 0 0 0 ;
4.096215385 4.429363462 4.719992 4.907214444 5.227143103 5.541824648 5.850966667 0 0 0 0 ;
4.902823077 5.302086538 5.64978 5.873674444 6.256731897 6.633349296 0 0 0 0 0 ;
5.336980769 5.771873077 6.1502 6.394043333 6.811125862 7.22114507 0 0 0 0 0 ;
7.255061538 6.611538462 6.243153333 6.10436 6.053547414 0 0 0 0 0 0 ;
8.675807692 7.906665385 7.466062667 7.30002 7.239393966 0 0 0 0 0 0 ;
10.04953846 9.052298077 8.514525333 8.338423333 0 0 0 0 0 0 0 ;
11.05449231 9.957344231 9.366130667 9.172244444 0 0 0 0 0 0 0 ;
13.30755769 11.71417692 10.73216267 10.30784556 0 0 0 0 0 0 0 ;
14.93913846 13.15035 12.04777067 0 0 0 0 0 0 0 0 ];
%Interploated value at 45 and 2900:
interp2(y,x,Z,2900,45)
%Plot the graph:
[X,Y] = meshgrid(x,y);
Zq = interp2(y,x,Z,Y,X);
surf(Y,X,Zq)
