SplitTester - Great Free Tool for Validating Test Results

A co-worker recently shared this free tidbit with me, and it's been so helpful that I wanted to share it here. It's called SplitTester, and it was developed by Brian Teasley and Perry Marshall. The way it works is simple: you enter clicks and click-through rate for two test cells, and it spits back the likelihood of the test having the same long-term results, along with the confidence level.
If you're a stats genius, you probably won't need this tool. But for the rest of us, it's a great way to quickly make sure that you're making statistically significant decisions. Not only can it be used for click-through prediction, but I've used it for conversion rate prediction as well - which is actually more relevant, anyway.

Check it out, and let me know what you think!