Elementary Statistics Unit 2 Formative Guide
1) Which cannot be a probability?
a) -1
b) 1
c) 0
d) .5
2) If a fair coin is flipped three times, what is the probability of getting a heads on the first toss
and a tails on the second and third tosses?
a) 3/6 b) 3/2 c) 1/8 d) 1/6 e) 3/8
3) If the probability of getting an event A is defined, what is the probability of not getting the
event A called?
a) sample space b) independent c) dependent d) exclusive e) complement
4) If an automobile manufacturer makes ignition keys by making 8 cuts, any one of four levels
deep, how many different keys can be made?
a) 4096 b) 8 c) 500 d) 78125 e) 65536
5) The sum of the probabilities of a discrete random variable is always equal to
a) 0 b) 100 c) 1
d) always different
e) the probabilities
6) The range a probability will fall within is
a) 0 < P(x) < 1
b) -1 < P(x) < 1
c) 0 < P(x) < 100
d) always changes
7) The result of a recent study on the side effects of using the Asthma medication Accolate
showed that 45 people experienced digestive disorders. The sample size used for the study
was n = 385. What is the probability that a randomly chosen person that uses Accolate for
treatment of Asthma will experience digestive disorders?
a) .1046
b) 8.55
c) .2715
d) .5388
e) .1169
8) The expected value of a discrete random variable is equal to its
a) standard deviation
b) variance c) median d) mean
9) If a computer randomly selects the last digit of a telephone number, find the
probability that it is odd or greater than 5.
a) .7 b) .8 c) .9
d) 1
e) .6 f) .5
10) If one event is not effected by the occurrence of another, they are said to be
a) dependent
b) independent
c) mutually exclusive d) deductive
11) If random guesses are made on two true-false questions and three five-part multiple
choice questions, what are the chances of getting them all correct?
a) .002 b) .001
c) 200 d) .0004
e) .005
12) Events that cannot occur at the same time are said to be
a) deductive b) mutually exclusive
c) independent
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d) dependent
Elementary Statistics Unit 2 Formative Guide
13) When the ordering of outcomes does matter, we are looking for
a) permutations
b) combinations
c) events
d) occurrences
14) A discrete random variable assigns ____________ to its inputs.
a) percentages
b) probabilities
c) totals
d) rates
e) integers
15) The list of all possible outcomes on an experiment is called the
a) sample space
b) random collection
c) event space
d) experiment space
16) If you played a lottery and you had to pick 4 correct numbers out of a
possible 24 numbers, what is your chance of winning if you play one time?
a) .00002
b) 6
c) .000094
d) .0035
17) What is the probability of getting 7 girls in 9 births? (assume 50% chance
of getting a girl on any given birth)
a) .07
b) .11
c) .23
d) .777
18) How many different ways can 6 people be arranged in 6 chairs?
a) 40320
b) 120
c) 720
d) 721
19) Given n=150 and p=.3, find the standard deviation of the binomial distribution.
a) 50
b) 5.6
c) 45
d) 31.5
Given the following discrete random variable, compute the mean and standard deviation.
_3.895___20) Mean
X
P(x)
2
3
4
5
.005
.195
.7
.1
___.55___ 21) standard deviation
22) Sampling where every element in the population has an equally likely chance of
being selected is called
a) convenience
b) probable
c) empirical
d) random
23) If the probability of getting at least one broken egg in a carton of 12 is .33, what is the
probability of not getting any broken egss?
a) .33
b) .45
c) .67
d) .5
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Elementary Statistics Unit 2 Formative Guide
24) The probability of getting heads on a single coin toss is
a) .5
b) less than .5
c) more than .5
d) don’t know
25) A local restaurant has found that 60% of its reservations are for nonsmoking tables,
while 40% are for tables for smokers. Find the probability that 3 randomly selected
reservations are all for nonsmoking tables.
a) .216
b) .784
c) .064
d) .60
26) A pollster must randomly select 3 of 12 available people. How many different groups
of 3 are possible?
a) 4
b) 36
c) 220
d) 1320
27) How many different batting line-ups are possible if a coach has 15 players on the
team and 11 players are in the batting order?
a) 65
b) 39916800 c) 5.44 E10 d) 1365
28) The probability of finding a broken cookie in a bag of chocolate chip cookies is
P = .03. Find the probability of getting at least 2 broken cookies in a bag containing 36
cookies.
a) .91
b) .294
c) .33
d) .06
Circle T for true or F for false for the following statements.
T
F
29) A probability distribution gives the probability for each value of the
random variable.
T
F
30) A discrete random variable has either a finite number of values or a
countable number of values.
T
F
31) Arrangements or sequences where order does not matter are called
permutations.
T
F
32) The Empirical approach to probability is when you run an
experiment and check the outcome to estimate the probability of a
similar experiment.
T
F
33) If a garage door opener has one set of 10 switches where the switches
could be in one of three positions, a person could set all possible
positions in less than ten minutes.
(one position per second).
T
F
34) A person can be convicted at a legal trial exclusively on probabilities.
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