Statistics::ChiSquared is not a suitable package except for preliminary investigation, as it returns a text string which you have to parse the numbers out of, but more importantly as it doesn't return the correct numbers, but rounds everything off to the nearest 5% (and appears to have some special love of 30% and 70%).
If every mathematical package returned a text string explaining the result rather than the result, because they don't trust you to interpret the result correctly, using Perl for math would be hell.
Note the documentation says "use Statistics::Chisquare", but correct usage is "use Statistics::ChiSquare".