Exam Rehearsal for probability and a little bit of statistics as well.

2. Probability Exam Rehearsal
In a family of three children, what is the probability that 2 of the children will be girls?
Photo source: kids in bali

3. Assuming equally likely probabilities for male and female births, what is
the probability that a four-child family will have at least one boy?
(a) (b) (c) (d)

4. In an experiment, two regular dice are rolled. Event A represents rolling the
same number on each die. How many outcomes in the total sample space
represent the complement, ?
(a) 6 (b) 12 (c) 24 (d) 30

5. How many different 10-digit telephone numbers can be created if the area
code (first three digits) is 250 or 604 and the exchange (second three digits) is
531, 535 or 540?
(a) 50 000 (b) 60 000 (c) 80 000 (d) 90 000

6. The diagram below right shows a partial map of a
certain city park, with walking paths located on the
grid lines. A tourist starts at point A and randomly
selects a path to point C, walking only to the south
and east. What is the probability the tourist passes
through point B?
(a) (b) (c) (d)

7. Companies A, B and C are bidding on a contract. From past records, it is known
that companies A and B are equally likely to get the contract, while company C
has half the likelihood of either A or B. What is the probability that company C
will get the contract?
(a) 0.20 (b) 0.25 (c) 0.30 (d) 0.40

8. Suppose there is an 80% chance that customs officers will ask to inspect your
luggage upon entering Canada. For 100 randomly selected travellers entering
Canada, what is the probability that exactly 85 will have their luggage
inspected?
If 240 tarvellers enter Canada at the Winnipeg International Airport, construct
at 95% confidence interval for the number of travellers who will have their
luggage inspected.