Question

1) Research from a big private university show that 7 out of 10 graduating seniors completed the major they intended when they enrolled at the school. What is the probability that a particular student completed her/his intended major?

2) Research from a big private university show that 7 out of 10 graduating seniors completed the major they intended when they enrolled at the school. What is the probability that two randomly selected students both completed their intended major?

3) Research from a big private university show that 7 out of 10 graduating seniors completed the major they intended when they enrolled at the school. What is the probability that two randomly selected students completed a different major than the one they intended?

Answer 1

solution:

1)

the given proportion of seniors who completed the major they intended = 7 / 10 = 0.7

so required probability of a senior completed the intended major = 0.7

2)

probability of senior completed the intended major = p = 0.7

probability that two randomly selected students completed their intended major = 0.7 * 0.7 = 0.49

so required probability = 0.49

3)

probability of completed the major they intended =p = 0.7

robability of completint the major other than they intended= q = 1 - 0.7 = 0.3

probability that two randomly selected students completed major other than they intended = 0.3 * 0.3 = 0.09

so required probability = 0.09