my comment re blackjack involved no counting...i was just playing basic strategy, i KNOW the casino has a long term 0.5% edge over me...point was that i was just lucky that i won after playing 300 hands...eddie is thinking if he does 300 trades and makes money, he must have an edge, alternatively if he does not make money, then he does not have an edge...i'm pointing out you can't tell either way from such a small sample size.
Playing 1000 hands of blackjack after memorising basic strategy should be compulsory for new traders. If we are talking small edges then your comment about 300 hands not being sufficient holds. If you have a large edge though this will become evident over a smaller sample.