This is a question of probability. The solution is to classify these data according to known conditions and see how much a specified category accounts for the whole. As can be seen from the problem, only more than 80% of the output is up to standard. From this point of view, the output of +30+3+4+2+3+ 100 in these eight days is up to standard, and the success rate is 8 divided by 10 = 0.