If you try to figure out how the value of one coin effects the pair, you will drive yourself mad.. What about the fluctuations in USD.. if BTC goes up, could it be being influenced because USD is going down? and now your thinking about forex calculations.. its never ending.. heres the thing, if you read the chart of the pair you are about to trade, and every trade you would have taken in the past would have worked out for you, then you will know your odds of success, and thats really as complicated as it needs to get..