A/B test for statistical significance

Question

I'm running an a/b test on an advertisement and I'd like to test for statistical significance. How would I design a test and prove whether or not conversions/clicks are statistically different from test A and test B?

Test A: 1000 clicks, 900 conversions

Test B: 380 clicks, 320 conversions

Thanks for your help guys.

Answer 1

I had a different answer here earlier, but now I'm pretty sure it was wrong. There are numerous online calculators for determining whether or not results like these are statistically significant. They all seem to use a form of Chi squared test.

So the answer to your question is: Don't design a new test for this purpose. Use what appears to be the standard test (Chi squared).