Create a graph using ITA method

I used following codes to create graph using ITA method.So, how can I increase the length of two lines near 1:1 line. Also how can I create vertical lines in -1.5 and 1.5 points.

Codes :-

dataset=xlsread('Allai Tank - SPI.xlsx','SPI 12','B3:B49');

piece = 2;

xmin=min(dataset);

xmax=max(dataset);

m = length(dataset);

if mod(m,2)~=0;

dataset=dataset(2:end);

m=m-1;

end

n=m/2;

x=dataset(1:n);

x=sort(x);

meanx=mean(x);

y=dataset(n+1:m);

y=sort(y);

Dv = 10*(y-x)/meanx;

D = mean(Dv);

k = length(Dv);

pin = k/piece;

for ii = 1:piece-1

num(ii) = floor(ii*pin);

end

num(piece) = n;

arrspl{1} = Dv(1:num(1));

for ii = 2:piece

arrspl{ii} = Dv(num(ii-1)+1:num(ii));

end

%Dvpie = arrspl{ii}

for ii = 1:piece

Dmm(ii) = mean(arrspl{ii});

end

if figure~=0

plot(x,y,'.','markersize',15);

hold on

axis([xmin*2.5 xmax*1.5 xmin*2.5 xmax*1.5])

plot([xmin*2.5,xmax*4],[xmin*2.5,xmax*4]);%1:1 line

% 10%Ïß

A=meanx*1;

plot([A,xmax*2+A],[0,xmax*2],'-','color',[0.23 0.695 0.125]);

plot([0,xmax*2],[A,xmax*2+A],'-','color',[0.93 0.695 0.125]);

end