How can I add a a best fit line, a scatter plot data? having trouble

% using the excel data 
[FileName, PathName] = uigetfile('*.xlsx','Select Excel files to analyze:','MultiSelect','off');
[status, sheets] = xlsfinfo([PathName, FileName]);
data_summary = xlsread([PathName, FileName],sheets{1});
% using struct to structure the data
data = struct('Heights',[],'Qs',[]); 

data.heights=(data_summary(1:5,1));
data.flowrates=(data_summary(1:5,2:11));

figure (1)
for i=1:5
    subplot(2,3,i)
    histogram(data.flowrates(i,1:10),10)
    xlabel('Volumetric flow rates [mL/s]','FontSize',10,'FontWeight','bold');
    ylabel('Number of occurances','FontSize',10,'FontWeight','bold');
    legend(['water exit height=' num2str(data.heights(i))]);
end

% Adding the average flow rate histogram
Qavg=mean(data.flowrates,2);
Qstd=std(data.flowrates,0,2);
errQ=Qstd./2;
subplot(2,3,6)
% fit=polyfit(data.flowrates,1);
% plot(polyval(fit,data.heights))
errorbar(data.heights,Qavg,errQ,'ro')
xlabel('Water exit height [cm]','FontSize',10,'FontWeight','bold');
ylabel('Flow rate [ml/s]','FontSize',10,'FontWeight','bold');


**
% I keep getting an error with what I have so far 

[Rik]

You did not attach the excel file, nor did you post the complete error message.

Answer 1

[Cris LaPierre]

I'd use polyfit.

This example shows you to do a simple linear regression.

x = 1:50; 
y = -0.3*x + 2*randn(1,50); 
p = polyfit(x,y,1); 

f = polyval(p,x); 
plot(x,y,'o',x,f,'-') 
legend('data','linear fit') 

Answer 2

[Saeed Bello]

Just add lsline after your scatter plot expression. For example

scatter(x,y)
lsline