100
200
300
400
Probability Distn
Into to Statistics JeopardyProbability
500
600
100
200
300
400
500
600
Credits
Probability - 100
Answer
Which of the following is not a valid probabilitya.) 2/3b.) 1/8c.) .70d.) 5/4
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.) ¼b.) ¾c.) ½d.) 1
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 b.) 1/3c.) 1/5d.) 1/9
Probability - 400
Answer
If a person is randomly selected, find the probability that his or her birthday is in May. Ignore leap years.
a.) 31/365b.) 1/31c.) 1/365d.) 1/12
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. e) A and B only.
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?
a.) 10/61b.) 1/61c.) 51/61d.) 10/51
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 - 100Probability Distn - 100
Answer
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
Probability Distn - 200Probability Distn - 200
Answer
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
Probability Distn - 300Probability Distn - 300
Answer
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.) 0.3456b.) 0.8208c.) 0.4752d.) 0.5248
Probability Distn - 400Probability Distn - 400
Answer
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.
a.) 0.3456b.) 0.8704c.) 0.5248d.) 0.1296
Probability Distn - 500Probability Distn - 500
Answer
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.
Probability Distn - 600Probability Distn - 600
Answer
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
Probability Distn - 100 Ans.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.Probability Distn - 200 Ans.
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
X 0 1 2 3 4 5
P(x) 0.129 0.312 -0.094 0.084 0.192 0.375
Determine whether the following is a valid probability distribution
Probability Distn - 300 Ans.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.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.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.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