Chpt. 11, Probability and Statistics

Question 1

Fundamental Counting Principle

Answer 1

in a sequence of selections, you can multiply the number of choices for each selection, and the product is the total number of possible overall outcomes

Question 2

permutation

Answer 2

an arrangement of items in a particular order

the number of n objects taken r at a time is:

p = n!/(n - r)!

Question 3

n factorial (!)

Answer 3

for any positive integer n, n factorial is n * n-1 * n-2, all the way down to zero

Question 4

combination

Answer 4

any unordered selection of r objects from a set of n objects

the number of combinations of n objects taken r at a time is:

C = n!/r!(n-r)!

Question 5

experimental probability

Answer 5

the ratio of the number of times something actually happens over the number of times the experiment has been done

Question 6

simulation

Answer 6

a model that imitates one or more events

Question 7

sample space

Answer 7

the set of all possible outcomes of an experiment

Question 8

equally likely outcomes

Answer 8

events in a sample space that have the same chance of occurring

Question 9

theoretical probability

Answer 9

if a sample space has n possible outcomes, and an event A occurs in m of these outcomes, then the theoretical probability of events a is P(A) = m/n

Question 10

dependent events

Answer 10

when the outcome of one event determines the outcome of a second event

Question 11

independent events

Answer 11

when the outcome of one event does not affect the probability of a second event

Question 12

mutually exclusive events

Answer 12

when two events cannot happen at the same time

Question 13

the probability of events A occurring and event B occurring also

Answer 13

P(A) * P(B)

Question 14

conditional probability

Answer 14

conditional probability contains a condition that may limit the sample space for an event; for example:
(train arrives and departs on time) train departs on time)

Question 15

measures of central tendency

Answer 15

mean, median, and mode

Question 16

mean

Answer 16

the sum of the data divided by the number of data

Question 17

median

Answer 17

the middle value in a set of data; if the data set contains an even number of values, this is the mean of the two middle values

Question 18

mode

Answer 18

the most frequently occurring value (or values) in a set of data; a data set may have no mode, one mode, or more than one mode

Question 19

bimodal

Answer 19

having multiple modes

Question 20

outlier

Answer 20

a value substantially different from the rest of the data in the set

Question 21

range (of a set of data)

Answer 21

the difference between the greatest and least values

Question 22

quartile

Answer 22

values that separate a finite data set into four equal parts; the second quartile is the median of the data; the first and third quartiles are the medians of the upper and lower halves of the data, respectively

Question 23

interquartile range

Answer 23

the difference between the third and first quartiles

Question 24

box and whisker plot

Answer 24

a method of displaying data that uses quartiles to form the center box, and the maximum and minimum values to form the whiskers

Question 25

percentile

Answer 25

a number from 0 to 100 that can be associated with a value x from a data set

Question 26

measures of variance

Answer 26

measures (such as the range, interquartile range, or standard deviation) that describe how the data in a data set are spread out

Question 27

variance

Answer 27

the square of the standard deviation

Question 28

standard deviation

Answer 28

a measure of how much the values in a data set vary (deviate) from the mean, X; standard deviation:

• find the mean
• square the difference between each point and the mean
• find the mean of the squares
• take the square root of the mean of the squares

Question 29

population

Answer 29

the members of a set

Question 30

sample

Answer 30

a portion of a population

Question 31

convenience sample

Answer 31

a sample in which all selected data points are those that are readily available (convenient)

Question 32

self-selected sample

Answer 32

a sample of data points selected by the sampler

Question 33

systematic sample

Answer 33

a sample in which the population is ordered in some way, then selected from at random intervals

Question 34

random sample

Answer 34

a sample in which the data points are selected randomly

Question 35

bias

Answer 35

a systematic error introduced by the sampling method

Question 36

observational study

Answer 36

when the sample is interacted with in such a way that it is not affected

Question 37

controlled experiment

Answer 37

an experiment with a “control”

Question 38

survey

Answer 38

a sample in which every member is asked the same questions