intro stat question

Question

Data collected at the elementary schools in a county’s school districts showed that each year roughly 21% of students miss exactly one day of school, 19% miss 2 days, and 15% miss 3 or more days due to sickness. (Hint: You may find it helpful to enter the information into the remaining cells of the table.)

(a) What is the probability that a student chosen at random doesn't miss any days of school due to sickness this year?

(b) What is the probability that a student chosen at random misses at most one day?

(c) What is the probability that a student chosen at random misses at least two days?

Answer 1

(a) Well if they didn't miss any days of school you can just find 1 - P(1) - P(2) - P(>=3) using the percentages given (change them to decimals)

(b) This is p (0) + P(1)

(c) This is p (2) + p (>=3)