shade area under curve - CDF plot

Hi, I'm looking to shade/fill the area under the curve on a cdf plot. This is fairly simple when plotting x,y data using the area or fill function. However, I cant find a way to do it when plotting a cdf as you only use one column of data to construct the plot. Any help would be much appreciated.

Best regards, Ciara

Answer 1

[Star Strider]

I don’t understand what the problem is.

Try this:

mu = 1;
sd = 2;
x = linspace(mu-10*sd, 1.96);
CDF = normcdf(x, mu, sd);

figure(1)
area(x, CDF)

[C Ryan]

Hi Star Strider, thanks for your reply.I have attached my code below.What I'm not clear on is how to apply the area function when you only have one column of data as I do. Generally, you would have a set of x values and a corresponding set of y values, no? e.g. X = [1,7,3,4]; Y = [6,8,3,5]; area(X,Y) but in my case I am only taking data from one column "data=num(:,1);" in my xl file. I hope that helps to explain what I'm asking!

[num,txt,raw]=xlsread('test.xlsx');

data=num(:,1);

h = cdfplot(data); h.LineWidth = h.LineWidth + 1;

xlabel('Errors per sheet %','fontsize', 18)

ylabel('Proportion of values less than or equal to x','fontsize', 18)

title('(a) CDF - Evaluation of student errors n=2556', 'fontsize', 20)

set(gca,'fontsize',18)

[Star Strider]

The cdfplot function creates the necessary vectors for you:

data = 1 + 2*randn(1, 25);                      % Create Data

figure(1)
h = cdfplot(data);
hold on
area(h.XData, h.YData)
hold off

[C Ryan]

Thank you. This is what I've been trying to do.

[Star Strider]

As always, my pleasure.