Probability Distributions

Question 1: Fifty-three percent of the population possesses characteristic X. If 15 people are randomly selected from the population, what is the probability that exactly 9 possess characteristic X?

a) .2009
b) .1653
c) .1780
d) .1102

Question2: A researcher is interviewing groups of 15 people to determine how many of them have degrees in business. The data gathered will most likely be outcomes from a:

a) continuous random variable
b) discrete random variable
c) education random variable
d) interviewed random variable

Question 3: If the following binomial problem is approximated by the Poisson distribution, the probability is: Prob(x = 4 n = 600 and p = .011)

a) .0661
b) .1076
c) .1295
d) .1673

Question 4: Customers arrive randomly at a small boutique at a rate of 2.6 every ten minutes. What is the probability that exactly 3 customers arrive in a five-minute interval?

a) .0319
b) .0687
c) .9711
d) .0998

Question 5: The combinations part of the binomial formula compute the:

a) sample space
b) probability of a success
c) probability of a single sequence
d) number of sequences

Question 6: A discrete distributions that is used to describe the occurrence of rare events is:

a) binomial
b) Poisson
c) Hypergeometric
d) Chi-square

Question 7: In a binomial experiment, p is .83. If n = 12, what is the probability that x = 10?

a) 0.3277
b) 0.1784
c) 0.296
d) 0.2203

Question 8 : Consider the following discrete random distribution. What is the mean of the distribution?

a) 2.48
b) 0.85
c) 1.97
d) 1.26

Question 9: The graph of the binomial distribution, n = 20 and p = .50 is:

a) skewed right
b) skewed left
c) approximately symmetrical
d) bimodal

Question 10: There are 15 people in the job applicant pool. Ten of the people in the applicant pool wear glasses. If 4 people are randomly hired from the applicant pool, what is the probability that none of the people hired wear glasses?

a) 0.3409
b) 0.2748
c) 0.2133
d) 0.0037

Question 11: In a binomial experiment, p is .29 and n = 18. What is the standard deviation of this binomial distribution?

a) 1.925
b) 1.046
c) 2.129
d) 3.425

Question 12: Consider the following discrete random distribution. What is the standard deviation of the distribution?

a) 1.3619
b) 1.1701
c) 1.0063
d) 1.2648

Question 13: In a binomial experiment, p is .30. If n = 10, what is the probability that 2 <= 5?

a) 0.348
b) 0.5274
c) 0.803
d) 0.9127

Question 14: Perhaps the most widely known of all discrete distributions is the:

a) hypergeometric distribution
b) binomial distribution
c) normal distribution
d) Poisson distribution

Question 15: The office receptionist receives, on average, 2.43 calls every half hour. What is the probability that in a twenty-minute interval, the receptionist receives exactly 2 calls?

a) 0.3015
b) 0.2597
c) 0.2017
d) 0.1852

Question 16: There are 15 people in the job applicant pool. Ten of the people in the pool wear glasses. If 4 people are randomly hired from the applicant pool, what is the probability that exactly 3 wear glasses?

a) 0.4396
b) 0.3763
c) 0.2985
d) 0.2209

Question 17: The Poisson distribution can be used to approximate binomial distributions problems if:

a) n< 20 and n? p<= 7
b) n> 20 and n? p<= 7
c) n> 20 and n? p>=7
d) n< 20 and n? p>= 7

Question 18: Consider the following discrete random distribution. What is the variance of the distribution?

a) 1.56
b) 2.09
c) 1.37
d) 1.04

Question 19: Customers arrive randomly at a small boutique at a rate of 2.6 every ten minutes. What is the probability that more than 6 customers arrive in a ten-minute interval?

a) 0.232
b) 0.0171
c) 0.0653
d) 0.0982