ch 8 vocab

Question 1

the mode is

Answer 1

the value or values that occur most often

Question 2

weighted average of a data set

Answer 2

gives greater importance, or weight, to some values in the set than to others

Question 3

to find a weighted average,

Answer 3

multiply each value by its weight

Question 4

the expected value is

Answer 4

the weighted average of the possible outcomes

Question 5

the weight for each outcome is its

Answer 5

probability

Question 6

a box-and-whisker plot

Answer 6

shows the spread of a data set

Question 7

the interquartile range is the

Answer 7

difference between the 1st and 3rd quartiles

Question 8

a measure of variation is

Answer 8

a value that describes the spread of a data set

Question 9

the variance is

Answer 9

the average of the squared differences from the mean

Question 10

standard deviation is

Answer 10

the square root of the variance and is one of the most common and useful measures of variation

Question 11

an outlier is

Answer 11

an extreme value that is much less than or much greater than the other data values

Question 12

a population is

Answer 12

the entire group of people or objects that you want information about

Question 13

a census is

Answer 13

a survey of an entire population

Question 14

a sample is

Answer 14

part of the population

Question 15

random sample (probability sample) is

Answer 15

when every member of a population has an equal chance of being selected for a sample

Question 16

some non-random samples are:

Answer 16

convenience samples and self-selected samples

Question 17

a biased sample is

Answer 17

a sample that that may not be representative of a population

Question 18

in a biased sample, the population can be

Answer 18

underrepresented or overrepresented

Question 19

a statistic is

Answer 19

a number that describes a sample

Question 20

a parameter is

Answer 20

a number that describes a population

Question 21

you can use a statistic from a survey to

Answer 21

estimate a parameter

Question 22

individuals are

Answer 22

people, animals, or objects that are described by data

Question 23

an experiment

Answer 23

imposes a treatment on individuals to collect data on their response to the treatment

Question 24

an observational study

Answer 24

observes individuals and measures variables without controlling the individuals or their environment in any way

Question 25

in a controlled experiment,

Answer 25

two groups are studied under conditions that are identical except for one variable

Question 26

treatment group

Answer 26

receives treatment

Question 27

control group

Answer 27

used for comparison, does not receive treatment

Question 28

in a randomized comparative experiment,

Answer 28

the individuals are assigned to the control group or the treatment group at random, in order to minimize bias

Question 29

reliable experiments can be

Answer 29

repeated and can be expected to produce similar results each time

Question 30

hypothesis testing is

Answer 30

used to determine whether the difference in two groups is likely to be caused by chance

Question 31

null hypothesis states

Answer 31

that there is no difference between the two groups being tested

Question 32

mean is the

Answer 32

sum of the values in the set divided by the number of values. often represented as x repeating

Question 33

the median is

Answer 33

the middle value or the mean of the two middle values when the set is ordered numerically

Question 33

Null hypothesis rejected

Answer 33

The difference is too large

Question 34

Z-test

Answer 34

When the sample contains at least 30 individuals the z-test can be used to reject the null hypothesis if the z value is too large

Question 36

(section 8-5) simple random sample: members are chosen using a method that gives everyone an

Answer 36

equally likely chance of being selected

Question 37

(section 8-5) systematic sample: members are chosen using a pattern, such as

Answer 37

selecting every other person

Question 38

(section 8-5) stratified sample: the population is first divided into groups. then members are

Answer 38

randomly chosen from each group

Question 39

(section 8-5) cluster sample: the population is first divided into groups. a sample of the groups is

Answer 39

randomly chosen. all members of the chosen groups are surveyed.

Question 40

(section 8-5) convenience sample: members are chosen because they are

Answer 40

easily accessible

Question 41

(section 8-5) self-selected sample: members volunteer to

Answer 41

participate

Question 42

(section 8-5) a probability sample is a sample where every member of the population being sampled has a

Answer 42

nonzero probability of being selected

Question 43

(section 8-5) the margin of error of a random sample defines an

Answer 43

interval, centered on the sample percent, in which the population percent is most likely to lie

Question 44

(section 8-6) binomial theorem: patter that can help you

Answer 44

expand any binomial

Question 45

(section 8-6) binomial experiment consists of n independent trials whose

Answer 45

outcomes are either successes or failures

Question 46

(section 8-6) binomial probability: in a binomial experiment, the probability of r successes (0

Answer 46

P(r) = nCr x p^r q^n-r

Question 47

(Section 8-8) the expected value (EV) is the weighted average of the numerical

Answer 47

outcomes of a probability experiment