Statistics involving 200,000 schoolkids from 47 states in the last two weeks of September yielded an overall coronavirus infection rate of just .13 percent among students and .24 percent for staffers, according to Brown University economics Professor Emily Oster and her team of number-crunchers. The figures translate into what would be roughly 1.3 infections for a school with 1,000 kids in the two-week period, and 2.2 positive tests for every 1,000 staffers in the same time frame.