How to use integral...

I am trying to solve a problem that is defined by the integral of the product of a series of variables, which in my data set consist of measures of a flower.

The question is how to do it, because the example displayed on http://www.mathworks.com/help/matlab/ref/integral.html, is not very clear and I am probably coding something improper.

if true
  fun_wrong = @x exp(-1.^2).*log(x).^2;
fun_wrong = @x exp(-1.^2).*log(x).^2;
end

So far I am using correlation to find the correlation between c1 and c2 and c3 and c4, and, there is a strong correlation between c3 and c4. I would like to find out more metrics to be honest, I am bored of using the same statistics.

Reference 1. Analysis of incomplete multivariate data, written by J.L. Scaffer, published by Chapman and Hall and available on Google Books.