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Into to Statistics Jeopardy
Credits
Probability
Probability Distn
100
100
200
200
300
300
400
400
500
500
600
600
Probability - 100
Which of the following is not a valid probability
a.) 2/3
b.) 1/8
c.) .70
d.) 5/4
Answer
Probability - 200
On a multiple choice test with four possible answers for
each question, what is the probability of answering a
question correctly if you make a random guess?
a.) ¼
b.) ¾
c.) ½
d.) 1
Answer
Probability - 300
A bag contains 4 red marbles, 3 blue marbles, and 5 green
marbles. If a marble is randomly selected, what is the
probability that it is blue?
a.) 1/4
b.) 1/3
c.) 1/5
d.) 1/9
Answer
Probability - 400
If a person is randomly selected, find the probability that his
or her birthday is in May. Ignore leap years.
a.) 31/365
b.) 1/31
c.) 1/365
d.) 1/12
Answer
Probability - 500
An assignment of probability must obey which of the
following?
a) The probability of any event must be a number
between 0 and 1, inclusive.
b) The sum of all the probabilities of all
outcomes in the sample space must be
exactly 1.
c) The probability of an event is the sum of the
outcomes in the sample space which make up the
event.
d) All of the above.
e) A and B only.
Answer
Probability - 600
A class consists of 61 students, 10 of which are women. If a
student is chosen at random, what is the probability that the
student is not a women?
a.) 10/61
b.) 1/61
c.) 51/61
d.) 10/51
Answer
Probability - 100 Answer
Which of the following is not a valid probability
d.) 5/4
Probabilities are always a value between zero and 1
inclusive. Since 5/4 is greater than 1, it cannot be a valid
probability.
Probability - 200 Answer
On a multiple choice test with four possible answers for
each question, what is the probability of answering a
question correctly if you make a random guess?
a.) ¼
The numerator in our fraction indicates the number of
correct choices, the denominator is the total number of
choices.
Probability - 300 Answer
A bag contains 4 red marbles, 3 blue marbles, and 5 green
marbles. If a marble is randomly selected, what is the
probability that it is blue?
a.) 1/4
There are 3 blue marbles out of a total of 12 marbles, so the
probability of drawing a blue marble is 4/12 which reduces
to 1/4
Probability - 400 Answer
If a person is randomly selected, find the probability that his or
her birthday is in May. Ignore leap years.
a.) 31/365
There are 31 days in May out of 365 possible birthdays. (Note:
since not all months have the same number of days, we must
use days instead of months to find the probability.)
Probability - 500 Answer
An assignment of probability must obey which of the
following?
a) The probability of any event must be a number
between 0 and 1, inclusive.
b) The sum of all the probabilities of all
outcomes in the sample space must be
exactly 1.
c) The probability of an event is the sum of the
outcomes in the sample space which make up the
event.
d) All of the above.
a, b, and c are all true statements
Probability - 600 Answer
A class consists of 61 students, 10 of which are women. If a
student is chosen at random, what is the probability that the
student is not a women?
c.) 51/61
If there are 61 students, 10 of which are women, then there
must be 51 (61-10) which are not women. So the probability
of not selecting a woman is 51/61
Probability Distn - 100
Determine whether the following is a valid
probability distribution
X
1
2
3
4
P(x)
0.037
0.200
0.444
0.296
a.) Yes
b.) No
Answer
Probability Distn - 200
Determine whether the following is a valid probability
distribution
X
0
1
2
3
4
5
P(x)
0.129
0.312
-0.094
0.084
0.192
0.375
a.) Yes
b.) No
Answer
Probability Distn - 300
In a certain town, 60% of adults have a college degree. The
accompanying table describes the probability distn for the
number of adults (among 4 randomly selected adults) who
have a college degree
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
Find the probability
that there are at least 2
with college degrees.
a.)
b.)
c.)
d.)
Answer
0.3456
0.8208
0.4752
0.5248
Probability Distn - 400
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
Find the probability that
there are less than 3
people who have
college degrees.
Answer
a.)
b.)
c.)
d.)
0.3456
0.8704
0.5248
0.1296
Probability Distn - 500
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
Find the expected number (the mean number) of
people with college degrees from 4 randomly
chosen people.
Answer
Probability Distn - 600
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
Find the standard deviation for the number of
people who have college degrees out of 4
randomly selected people
Answer
Probability Distn - 100 Ans.
Determine whether the following is a valid probability
distribution
X
1
2
3
4
P(x)
0.037
0.200
0.444
0.296
b.) No
0 ≤ P(x) ≤ 1—This condition is met
∑ P(x) = 1– The sum of the probabilities = .977
which ≠ 1---so this condition is not met and the distn
is not valid
Probability Distn - 200 Ans.
Determine whether the following is a valid
probability distribution
X
0
1
2
3
4
5
P(x)
0.129
0.312
-0.094
0.084
0.192
0.375
b.) No
0 ≤ P(x) ≤ 1—This condition is not met and the
distn is not valid
∑ P(x) = 1– The sum of the probabilities = 1
Probability Distn - 300 Ans.
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
Find the probability
that there are at least 2
with college degrees.
b.) 0.8208
The probability of at least 2 having college
degrees is found by finding the sum of 2, 3, and 4
having degrees
Probability Distn - 400 Ans.
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
Find the probability that
there are less than 3
people who have
college degrees.
c.) 0.5248
The probability of less than 3 people having college
degrees is found by finding the sum of 2, 1, and 0
having degrees= .0256+.1536+.3456
Probability Distn - 500 Ans.
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
To find the expected value (the mean) of the
distribution
μx = ∑ x •P(x) =
0(.0256) + 1(.1536) + 2(.3456) + 3(.3456) + 4(.1296)=
2.4
TI-Tips:
X’s in list 1: P(x) in list 2:
1-var stats L1, L2
Probability Distn - 600 Ans.
X
0
1
2
3
4
P(x)
0.0256
0.1536
0.3456
0.3456
0.1296
To find the standard deviation:
σ=√∑(x-μ)2•P(x)
(0-2.4)2•.0256 + (1-2.4)2•.1536 + (2-2.4)2•.3456
+ (3-2.4)2•.3456 + (4-2.4)2•.1296 = .9798
Credits
Questions have come from the
Test Bank for
Basic Practice of Statistics
And
Essentials of Statistics