Page 138 - Probability Demystified

CHAPTER 7 The Binomial Distribution 127

2. The sum of the probabilities of all outcomes in a probability distribu-
tion is
a. 0
b. 1
c. 2
d. It varies

3. Which one is not a requirement of a binomial experiment?
a. There are 2 outcomes for each trial.
b. There is a fixed number of trials.
c. The outcomes must be dependent.
d. The probability of a success must be the same for all trials.
4. The formula for the mean of a binomial distribution is

a. np
b. np(1 p)

c. n(1 p)
p ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
d. npð1 pÞ
5. The formula for a standard deviation of a binomial distribution is

a. np
b. np(1 p)

c. n(1 p)
p ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
d. npð1 pÞ
6. If 30% of commuters ride to work on a bus, find the probability that
if 8 workers are selected at random, 3 will ride the bus.
a. 0.361
b. 0.482
c. 0.254
d. 0.323

7. If 10% of the people who take a certain medication get a headache,
find the probability that if 5 people take the medication, one will get a
headache.
a. 0.328
b. 0.136
c. 0.472
d. 0.215