evelyn goes to a middle school that includes grades 6, 7, and 8. she wants to estimate the percentage of students in the school who ride the bus to school. she selects a random sample of 200 students to survey who are attending an after-school activity. she determines that 38% of the students at the activity ride the bus to school. which statement about evelyn's sample is true? a. the sample is the percentage of students who ride the bus. b. the sample might not be representative of the population because it only includes students who are attending an after-school activity. c. the sample shows that exactly 38% of the students in the school ride the bus.