just to add, anything that has a <50% chance of winning is gambling. In casino, the highest odd is close to 50% and this is a akin to flipping of a coin. thats why in the long run, you still lose money.
real investors or traders must aim for a higher chance of winning ie 60 to 80% success rate. then this isn't considered gambling. and in the long run, you will earn money.
Untrue. You do not need a >50% hit rate to be profitable in the long run. All you need is a dutchbook against them (like casino and Singapore Pools had against you). A 50% hit rate with 1:1 pay rate will leave you with 0 net profit in the long run as (0.5*1)+(0.5*-1) = 0. A 20% hit rate with 1:5 returns will leave you in net profit in the long run (0.2*5)+(0.8*-1) = +0.2. And to add on, you can lose money even if you are having a 95% success rate, if your risk:reward ratio is mediocre.