34 A survey of 1020 adults aged 1849 years found that 34 of

34. A survey of 1020 adults aged 18-49 years found that 34% of them have no credit cards, 22% have one credit card, 28% have two or three credit cards, 11% have four or five credit cards, and 5% have more than five credit cards. What is the probability that a randomly chosen respondent in the survey has:

a. No credit card?

b. Between one and three credit cards?

c. Four or more credit cards?

Solution

a) Prob for a random person having no credit card = 34% =0.34

b) Prob for a random person having between one and 3 credit cards

= Prob for either 1 or 2 or 3 cards

= 0.22+0.28 = 0.50

c) Prob ( for a random person having 4 or more credit cards)

= 11% = 0.11