A large random sample of American students in seventh grade showed that 20%20\% 20% 20, percent of them were reading below grade
level. Based on this data, which of the following conclusions are valid?
A.20% of all American students in seventh grade were reading below grade level.
B. 20% of this sample was reading below grade level, but we cannot conclude anything about the population.
=> 8+x = 15 => x = 15-8=7
