WGU statistics Exam Questions and Answers 100%
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The probability of any event is between one and o. What is the equation for this?
For any event A, 0 ≤ P(A) ≤ 1.
The sum of all possible probabilities is___?
One, the equation is :P(S) = 1
What is the complement rule? or the probability that an event does not occur is 1 minus the
probability that it does occur.
P(not A) = 1 - P(A)
In probability, "OR" means either one or the other or both.
P(A or B) = P(event A occurs or event B occurs or both occur)
Two events that cannot occur at the same time are called
disjoint or mutually exclusive
The Addition Rule for Disjoint Events:
If A and B are disjoint events, then P(A or B) = P(A) + P(B).
P(A and B) =
P(event A occurs and event B occurs)
The idea of disjoint events is
is about whether or not it is possible for the events to occur at the same time
The idea of independent events is about
whether or not the events affect each other in the sense that the occurrence of one event affects the
probability of the occurrence of the other
If A and B Disjoint
A and B can not be indepentdent
If A and B are two independent events (Multiplication Rule)
P(A and B) = P(A) * P(B).
if A, B and C are three independent events,
P(A and B and C) = P(A) P(B) P(C)
The Complement Rule,
P(A) = 1 - P(not A),
, P(L) = 1 - P(not L) = 1 - P(not O1 and not O2 and not O3 and not O4 and not O5 and not O6 and not O7
and not O8 and not O9 and not O10).
Applying the Multiplication rule:Now, using the multiplication rule, = 1 - (.56 .56 .56 .56 .56 .56 .56 .56
.56 * .56) = 1 - .003 = .997.
P(at least one person chosen has blood type O)
P((O and O) or (O and not O) or (not O and O)) = (.44 .44) + (.44 .56) + (.56 * .44) = .6864.
If A and B are disjoint events -
P(A and B)= 0
The General Addition Rule states that for any two events,
P(A or B) = P(A) + P(B) - P(A and B)
When each of two outcomes has two possible values (yes/no),
there are four possible combinations altogether, which correspond to the four possible outcomes.
How do we build a two-way table of probabilities?
Horizontally, A, not A and total, Vertically, B. not B and total
In a two-way table of probabilities, what is the total of all outcomes (lower right corner?)
1
Two events A and B are independent if any one of the following hold:
P(B | A) = P(B)
P(A | B) = P(A)
P(B | A) = P(B | not A)
P(A and B) = P(A) * P(B)
In general, another method for checking the independence of events A and B is to compare
P(A and B) to P(A) * P(B). If the two are equal, then A and B are independent, otherwise the two are
not independent.
"one in every thousand people (0.001) of all individuals are infected with HIV (H) - give equasion
P(H) = .001
If someone actually has HIV, the probability of testing positive is .95" (H) give equasion
P(T | H) = .95
Use the General Multiplication Rule to find the probability that someone chosen at random from the
population has HIV and tests positive. (H is HIV positive and probability of HIV+ test accuracy is .95)
P(H and T) = P(H) * P(T given H) = .001 x .95 = .00095.
Pass
The probability of any event is between one and o. What is the equation for this?
For any event A, 0 ≤ P(A) ≤ 1.
The sum of all possible probabilities is___?
One, the equation is :P(S) = 1
What is the complement rule? or the probability that an event does not occur is 1 minus the
probability that it does occur.
P(not A) = 1 - P(A)
In probability, "OR" means either one or the other or both.
P(A or B) = P(event A occurs or event B occurs or both occur)
Two events that cannot occur at the same time are called
disjoint or mutually exclusive
The Addition Rule for Disjoint Events:
If A and B are disjoint events, then P(A or B) = P(A) + P(B).
P(A and B) =
P(event A occurs and event B occurs)
The idea of disjoint events is
is about whether or not it is possible for the events to occur at the same time
The idea of independent events is about
whether or not the events affect each other in the sense that the occurrence of one event affects the
probability of the occurrence of the other
If A and B Disjoint
A and B can not be indepentdent
If A and B are two independent events (Multiplication Rule)
P(A and B) = P(A) * P(B).
if A, B and C are three independent events,
P(A and B and C) = P(A) P(B) P(C)
The Complement Rule,
P(A) = 1 - P(not A),
, P(L) = 1 - P(not L) = 1 - P(not O1 and not O2 and not O3 and not O4 and not O5 and not O6 and not O7
and not O8 and not O9 and not O10).
Applying the Multiplication rule:Now, using the multiplication rule, = 1 - (.56 .56 .56 .56 .56 .56 .56 .56
.56 * .56) = 1 - .003 = .997.
P(at least one person chosen has blood type O)
P((O and O) or (O and not O) or (not O and O)) = (.44 .44) + (.44 .56) + (.56 * .44) = .6864.
If A and B are disjoint events -
P(A and B)= 0
The General Addition Rule states that for any two events,
P(A or B) = P(A) + P(B) - P(A and B)
When each of two outcomes has two possible values (yes/no),
there are four possible combinations altogether, which correspond to the four possible outcomes.
How do we build a two-way table of probabilities?
Horizontally, A, not A and total, Vertically, B. not B and total
In a two-way table of probabilities, what is the total of all outcomes (lower right corner?)
1
Two events A and B are independent if any one of the following hold:
P(B | A) = P(B)
P(A | B) = P(A)
P(B | A) = P(B | not A)
P(A and B) = P(A) * P(B)
In general, another method for checking the independence of events A and B is to compare
P(A and B) to P(A) * P(B). If the two are equal, then A and B are independent, otherwise the two are
not independent.
"one in every thousand people (0.001) of all individuals are infected with HIV (H) - give equasion
P(H) = .001
If someone actually has HIV, the probability of testing positive is .95" (H) give equasion
P(T | H) = .95
Use the General Multiplication Rule to find the probability that someone chosen at random from the
population has HIV and tests positive. (H is HIV positive and probability of HIV+ test accuracy is .95)
P(H and T) = P(H) * P(T given H) = .001 x .95 = .00095.
