Minimum clicks for A/B testing to be viable?

[merlin]

Guys,
My ad A has 100 impressions, and 3 clicks.
My ad B has 100 impressions, and 4 clicks.
My ad C has 100 impressions, and 1 click
my ad D has 100 impressions, and no clicks.

I guess this is not enough to say that B is better than A. But is it enough to dispose of C & D?

What is the equation that says that the results of testing are viable?

Thanks

[dacapo]

Originally Posted by merlin

Guys,
My ad A has 100 impressions, and 3 clicks.
My ad B has 100 impressions, and 4 clicks.
My ad C has 100 impressions, and 1 click
my ad D has 100 impressions, and no clicks.

I guess this is not enough to say that B is better than A. But is it enough to dispose of C & D?

What is the equation that says that the results of testing are viable?

Thanks

Not too familiar, but these click rates seem artificially high. Unless your the advertiser.. (apologies if that's the case).. I was thinking from my experience in seeing click rates as a publisher.