WGU academy- intro to statistics
probability checkpoint 2
A fair die is rolled 12 times. Consider the following three possible outcomes:
The three outcomes are equally likely.
Let A and B be two disjoint events such that P(A) = .30 and P(B) = .60.
A
What is P(A and B)?
VI
p(aa)+(bb)
TU
The following probabilities are based on data collected from U.S. adults during the
National Health Interview Survey 2005-2007. Individuals are placed into an activity
category based on the amount of weekly activity.
IS
InactiveIrregular Light ActivityRegular Light ActivityIrregular Vigorous ActivityRegular
Vigorous ActivityProbability0.3970.1920.1040.2330.074
OM
Based on these data, what is the probability that a randomly selected U.S. adult
participates in any vigorous activity?
p(v)= Irregular Vigorous Activity + Regular Vigorous Activity
NA
In a large population, 3% have had a heart attack. Suppose a medical researcher
JP
randomly selects two people.
Let X represent the event the first person has had a heart attack.
Let Y represent the event the second person has had a heart attack.
Which of the following is true about the two events?
X and Y are independent.
The next three questions refer to the following information.
, According to the information that comes with a certain prescription drug, when taking
this drug, there is a 20% chance of experiencing dizziness (D) and a 40% chance of
experiencing headaches (H). The information also states that there is a 15% chance of
experiencing both side effects.
What is the probability of experiencing dizziness or a headache?
0.45
p(d)+p(h)-p(d and h)
A
Here again is the information about the prescription drug: There is a 20% chance of
VI
experiencing dizziness (D) and a 40% chance of experiencing headaches (H). The
information also states that there is a 15% chance of experiencing both side effects.
What is the probability of experiencing only dizziness?
TU
0.05
p(d)-p(d and h)
IS
Here again is the information about the prescription drug: There is a 20% chance of
experiencing dizziness (D) and a 40% chance of experiencing a headache (H). The
information also states that there is a 15% chance of experiencing both side effects.
OM
What is the probability of experiencing neither of the side effects?
0.55
p(not d or h)
NA
A particular student has a lot of trouble getting up in the morning. To make sure he will
not oversleep, he sets four identical alarm clocks. Each of the four alarms will buzz at
the set time with a probability of .98 independently of the others.
What is the probability that when the set time arrives, all four alarms will buzz?
JP
(.98)4
The student, obviously, is interested in the probability that when the set time occurs, at
least one of the four alarms will buzz. This probability is equal to:
1 - (.02)4
probability checkpoint 2
A fair die is rolled 12 times. Consider the following three possible outcomes:
The three outcomes are equally likely.
Let A and B be two disjoint events such that P(A) = .30 and P(B) = .60.
A
What is P(A and B)?
VI
p(aa)+(bb)
TU
The following probabilities are based on data collected from U.S. adults during the
National Health Interview Survey 2005-2007. Individuals are placed into an activity
category based on the amount of weekly activity.
IS
InactiveIrregular Light ActivityRegular Light ActivityIrregular Vigorous ActivityRegular
Vigorous ActivityProbability0.3970.1920.1040.2330.074
OM
Based on these data, what is the probability that a randomly selected U.S. adult
participates in any vigorous activity?
p(v)= Irregular Vigorous Activity + Regular Vigorous Activity
NA
In a large population, 3% have had a heart attack. Suppose a medical researcher
JP
randomly selects two people.
Let X represent the event the first person has had a heart attack.
Let Y represent the event the second person has had a heart attack.
Which of the following is true about the two events?
X and Y are independent.
The next three questions refer to the following information.
, According to the information that comes with a certain prescription drug, when taking
this drug, there is a 20% chance of experiencing dizziness (D) and a 40% chance of
experiencing headaches (H). The information also states that there is a 15% chance of
experiencing both side effects.
What is the probability of experiencing dizziness or a headache?
0.45
p(d)+p(h)-p(d and h)
A
Here again is the information about the prescription drug: There is a 20% chance of
VI
experiencing dizziness (D) and a 40% chance of experiencing headaches (H). The
information also states that there is a 15% chance of experiencing both side effects.
What is the probability of experiencing only dizziness?
TU
0.05
p(d)-p(d and h)
IS
Here again is the information about the prescription drug: There is a 20% chance of
experiencing dizziness (D) and a 40% chance of experiencing a headache (H). The
information also states that there is a 15% chance of experiencing both side effects.
OM
What is the probability of experiencing neither of the side effects?
0.55
p(not d or h)
NA
A particular student has a lot of trouble getting up in the morning. To make sure he will
not oversleep, he sets four identical alarm clocks. Each of the four alarms will buzz at
the set time with a probability of .98 independently of the others.
What is the probability that when the set time arrives, all four alarms will buzz?
JP
(.98)4
The student, obviously, is interested in the probability that when the set time occurs, at
least one of the four alarms will buzz. This probability is equal to:
1 - (.02)4
