If youre asking for the formula to see just how unfortunate you were on these 10 swings, you got fairly unlucky. The odds of getting 7 or more fails in 10 tries should be about .00086 if i remember how to calculate these right. If youre asking because you think this in some way proves that the percentages shown are false or that the rng for the game is broken, then i hate to tell you that your data shows no such thing. Your data actually shows nothing at all, as 10 swings is not even remotely close to enough data to start approximating these things. This topic comes up periodically on the boards, and the answer is that the rng solution they use for the game is a good one. There was a post a couple years ago where one of the devs went into depth about it, and im sure someone can dig it up if you want to read it. But as with any rng approach that is supposed to be fairly random, any given short string of trials could be a streaky one. And because of the human tendency to remember the negative outcomes more then the positive ones(ever get a HQ craft without putting in any quality steps? or that 20% ore hitting 3 times in a row?), this has been debated repeatedly. Several people over the years have been convinced enough that they were right and math was wrong that they set out to run a large enough sample of tests(a dev could ask for a readout of the last x million trials to make sure the numbers are about right, an individual looking to replicate this would likely want to go 1000+ times and keep good notes) to prove their point. Most never come back with the results of their work(either because they never actually did it or because they didnt want to admit that their data proved them wrong is what i would guess), though one or two did in fact ultimately agree that the long-term averages were about right.