You can adjust your AWstats unique visitors vs hits and many other areas. Image Ads have a higher min. bid then text ads.
It's depend on your niches, Ad placements, and luck. For me, 50 clicks would score around $30 on the luckiest day and around $10 when things are not going well. Depend. Depend. Oh well, why don't you just tell us how much you are earning from that 50 clicks? What's your niches, how many blogs, and what is the ad placements that produce that 50 clicks?