Probability Flashcards
Each individual outcome of an experiment is called
a sample point
A graphical method of representing the sample points of an experiment is
a tree diagram
Any process that generates well-defined outcomes is
an experiment
In statistical experiments, each time the experiment is repeated
a different outcome may occur
The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is not important is called
combination
From a group of six people, two individuals are to be selected at random. How many possible selections are there?
15
A method of assigning probabilities based upon judgment is referred to as the
subjective method
A graphical device used for enumerating sample points in a multiple-step experiment is a
not a bar chart, a pie chart nor a histogram
The set of all possible outcomes of an experiment is
the sample space
If a dime is tossed four times and comes up tails all four times, the probability of heads on the fifth trial is
1/2
Of five letters (A, B, C, D, and E), two letters are to be selected at random. How many possible selections are there?
10
Assume your favorite football team has 2 games left to finish the season. The outcome of each game can be win, lose or tie. The number of possible outcomes is
9
An experiment consists of tossing 4 coins successively. The number of sample points in this experiment is
16
Since the sun must rise tomorrow, then the probability of the sun rising tomorrow is
not much larger than zero, zero nor infinity
If a coin is tossed three times, the likelihood of obtaining three heads in a row is
0.125
Of the last 100 customers entering a computer shop, 25 have purchased a computer. If the classical method for computing probability is used, the probability that the next customer will purchase a computer is
0.50
A six-sided die is tossed 3 times. The probability of observing three ones in a row is
1/216
A perfectly balanced coin is tossed 6 times and tails appears on all six tosses. Then, on the seventh trial
both heads and tails can appear
A method of assigning probabilities which assumes that the experimental outcomes are equally likely is referred to as the
classical method
The probability assigned to each experimental outcome must be
between zero and one
Some of the CDs produced by a manufacturer are defective. From the production line, 5 CDs are selected and inspected. How many sample points exist in this experiment?
32
Assume your favorite football team has 3 games left to finish the season. The outcome of each game can be win, lose, or tie. How many possible outcomes exist?
27
From nine cards numbered 1 through 9, two cards are drawn. Consider the selection and classification of the cards as odd or even as an experiment. How many sample points are there for this experiment?
4
If a six sided die is tossed two times, the probability of obtaining two “4s” in a row is
1/36
The intersection of two mutually exclusive events
must always be equal to 0
The range of probability is
zero to one
Two events, A and B, are mutually exclusive and each have a nonzero probability. If event A is known to occur, the probability of the occurrence of event B is
zero
The sum of the probabilities of two complementary events is
1.0
One of the basic requirements of probability is
if there are k experimental outcomes, then sumP(Ei) = 1
The symbol ‘or’ shows the
union of events
The union of events A and B is the event containing
all the sample points belonging to A or B or both
If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A ‘and’ B) =
0.00
Events A and B are mutually exclusive with P(A) = 0.3 and P(B) = 0.2. Then, P(B to the power of c) =
0.8
In an experiment, events A and B are mutually exclusive. If P(A) = 0.6, then the probability of B
cannot be larger than 0.4
If P(A) = 0.62, P(B) = 0.47, and P(A ‘or’ B) = 0.88, then P(A ‘and’ B) =
0.2100
If P(A) = 0.7, P(B) = 0.6, P(A ‘and’ B) = 0, then events A and B are
mutually exclusive
Two events with nonzero probabilities
can not be both mutually exclusive and independent
If A and B are independent events with P(A) = 0.65 and P(A ‘and’ B) = 0.26, then, P(B) =
0.400
If two events are independent, then
they must not be mutually exclusive, the sum of their probabilities must not be equal to one and their intersection must not be zero
The multiplication law is potentially helpful when we are interested in computing the probability of
the intersection of two events
If A and B are independent events with P(A) = 0.4 and P(B) = 0.6, then P(A ‘and’ B) =
0.24
If A and B are independent events with P(A) = 0.05 and P(B) = 0.65, then P(A | B) =
0.05
If A and B are independent events with P(A) = 0.4 and P(B) = 0.25, then P(A ‘or’ B) =
0.55
If A and B are independent events with P(A) = 0.38 and P(B) = 0.55, then P(A | B) =
0.38
If A and B are independent events with P(A) = 0.35 and P(B) = 0.20, then, P(A ‘or’ B) =
0.48
