How to fit a normal distribution curve to a bar graph?

I have a bar plot and I tried fitting a Gaussian distribution curve using normpdf, but it's not working. What am I doing wrong?

lx = linspace(1,32,32);
figure(1)
hold on
bar(diftn)
plot(lx,normpdf(diftn))

[parslee]

diftn =

0.0401

0.0422

0.0755

0.0914

0.1044

0.1358

0.1955

0.2271

0.2311

0.2337

0.3979

0.3490

0.4389

0.4626

0.7340

1.0000

1.0000

0.7340

0.4626

0.4389

0.3490

0.3979

0.2337

0.2311

0.2271

0.1955

0.1358

0.1044

0.0914

0.0755

0.0422

0.0401

Answer 1

[Matt J]

One way,

load diftn
x=(1:numel(diftn))';

fobj=fit(x,diftn,'gauss1');

plot(fobj,x,diftn)