MATLAB: How to change LineWidth and MarkerSize in plot fit curve

datafitlinewidthmarkersizeplotpoly1set

I am using this code in order to plot my data.
The problem is that I can not change the size and the linewidth of my plot.
I used this 
filename='final.txt'
d1= importdata(filename);
x=d1.data(:,1)
y=d1.data(:,2)
f=fit(x,y,'poly1')
plot(f,'r--',x,y,'b^','MarkerSize',10);
But no use. The problem is in command
plot(f,'r–',x,y,'b^','MarkerSize',10);
Command window shows
Error in test_trendline (line 17)
plot(f,'r–',Distance,IMM,'b^','MarkerSize',10);
Could you please help me?

Best Answer

Can you try this way? 
figure,plot(f,'r--');
hold on;
plot(x,y,'^b','MarkerSize',10);
May be because of different class, here 'f' is cfit class