ABBA: A/B Test (Split Test) Calculator
thumbtack.com
thumbtack.com
1) The multiple testing correction, which many people ignore when testing > 1 variants vs. the control
2) They display not only the p-value, but the confidence interval around the _difference_ between the variants (i.e. the effect size). It's tempting to observe an increase of say 50% that is statistically significant and think that you can be confident about the 50%. This is not the case! You chose your sample size to be confident that the actual effect size is > 0 -- not that you would have a tight confidence interval around whatever difference you observed. Depending on your sample, the lower bound could still be close to 0.
"Sorry, this request is coming from a country which we currently do not support. If you feel this is in error, please contact our support team by emailing support@thumbtack.com."
I guess even blogs and articles are now coming under region protection.
Anyways there is a version or ABBA usable on github or you can always get the source and run it locally:
I've gotten blocked from a couple of sites I was managing because I was in Japan.