Exam 1

Question 1

population

Answer 1

the large group of individuals to which the law of nature applies

Question 2

sample

Answer 2

a relatively small subset of a population intended to represent the population

Question 3

participants

Answer 3

the individuals who are measured in a sample

Question 4

variable

Answer 4

anything about a behavior or situation that, when measured, can produce two or more different scores

Question 5

quantitative variable

Answer 5

A variable for which scores reflect the amount of the variable that is present

Question 6

qualitative variable

Answer 6

A variable for which scores reflect a quality or category that is present

Question 7

relationship

Answer 7

A pattern between two variables where a change in one variable is accompanied by a consistent change in the other

Question 8

descriptive statistics

Answer 8

Procedures for organizing and summarizing sample data

Question 9

inferential statistics

Answer 9

Procedures for determining whether sample data accurately represent the relationship in the population

Question 10

statistic

Answer 10

A number that describes a sample of scores; symbolized by a letter from the English alphabet

Question 11

parameter

Answer 11

A number that describes a population of scores; symbolized by a letter from the Greek alphabet

Question 12

design

Answer 12

The way in which a study is laid out

Question 13

nominal scale

Answer 13

A scale in which each score is used for identification and does not indicate an amount

Question 14

ordinal scale

Answer 14

A scale in which scores indicate rank order

Question 15

interval scale

Answer 15

A scale in which scores measure actual amounts; but zero does not mean zero amount is present, so negative numbers are possible

Question 16

ratio scale

Answer 16

A scale in which scores measure actual amounts and zero means no amount of the variable is present, so negative numbers are not possible

Question 17

continuous variable

Answer 17

A variable that can be measured in fractional amounts

Question 18

discrete variable

Answer 18

A variable that cannot be measured in fractional amounts

Question 19

raw scores

Answer 19

the scores initially measured in a study

Question 20

frequency

Answer 20

A variable that cannot be measured in fractional amounts

Question 21

frequency distribution

Answer 21

A distribution showing the number of times each score occurs in the data

Question 22

bar graph

Answer 22

A graph showing a vertical bar over each X score, but adjacent bars do not touch; used with nominal or ordinal scores

Question 23

histogram

Answer 23

Afrequency graph similar to a bar graph but with adjacent bars touching; used with a small range of interval or ratio scores

Question 24

frequency polygon

Answer 24

Afrequency graph showing a data point above each score, with the adjacent points connected by straight lines; used with many different interval or ratio scores

Question 25

data point

Answer 25

A dot plotted on a graph to represent a pair of X and Y scores

Question 26

grouped distribution

Answer 26

A distribution created by combining individual scores into small groups and then reporting the total frequency (or other description) of each group

Question 27

normal curve

Answer 27

The symmetrical, bell-shaped curve produced by graphing a normal distribution

Question 28

normal distribution

Answer 28

A set of scores in which the middle score has the highest frequency and, proceeding toward higher or lower scores, the frequencies at first decrease slightly but then decrease drastically, with the highest and lowest scores having very low frequency

Question 29

tail of the distribution

Answer 29

The far-left or far-right portion of a frequency polygon containing the relatively low-frequency, extreme scores

Question 30

negative skew distribution

Answer 30

An asymmetrical distribution with lowfrequency, extreme low scores, but without corresponding low-frequency, extreme high scores; its polygon has only one pronounced tail, over the lower scores

Question 31

positive skew distribution

Answer 31

An asymmetrical distribution with lowfrequency, extreme high scores, but without corresponding low-frequency, extreme low scores; its polygon has only one pronounced tail, over the higher scores

Question 32

bimodal distribution

Answer 32

A distribution forming a symmetrical polygon with two humps where there are relatively highfrequency scores, with center scores that have the same frequency

Question 33

relative frequency

Answer 33

The proportion of time a score occurs in a distribution

Question 34

proportion of the area under the curve

Answer 34

The proportion of the total area under the normal curve at certain scores, which represents the relative frequency of those scores

Question 35

cumulative frequency

Answer 35

The number of scores in the data that are at or below a particular score

Question 36

EX

Answer 36

sum of x

Question 37

measures of central contigency

Answer 37

Statistics that summarize the location of a distribution on a variable by indicating where the center of the distribution tends to be located

Question 38

mode

Answer 38

A score having the highest frequency in the data

Question 39

unimodal

Answer 39

A distribution whose frequency polygon has only one hump and thus has only one score qualifying as the mode

Question 40

bimodal

Answer 40

A distribution whose frequency polygon shows two humps, each centered over a score having the highest frequency, so there are two modes

Question 41

median

Answer 41

The score located at the 50th percentile

Question 42

mean

Answer 42

The score located at the mathematical center of a distribution

Question 43

x

Answer 43

The symbol used to represent the sample mean

Question 44

deviation

Answer 44

The distance a score is from the mean; indicates how much the score differs from the mean

Question 45

sum of deviations around the mean

Answer 45

The sum of all differences between the scores and the mean; symbolized by E(X-XBAR)

Question 46

line graph

Answer 46

A graph of an experiment’s results when the independent variable is an interval or ratio variable; plotted by connecting data points with straight lines; as opposed to a bar graph, used when the independent variable is a nominal or ordinal variable

Question 47

measure of variability

Answer 47

Statistics that summarize the extent to which scores in a distribution differ from one another

Question 48

range

Answer 48

The distance between the highest and lowest scores in a set of data

Question 49

sample variance

Answer 49

The average of the squared deviations of scores around the sample mean. S^2vx

Question 50

sample standard deviation

Answer 50

The square root of the sample variance; interpreted as somewhat like the “average” deviation. Svx

Question 51

population standard

Answer 51

The square root of the population variance, or the square root of the average squared deviation of scores around the population mean . omegavx

Question 52

population vaiance

Answer 52

The average squared deviation of scores around the population mean. omega^2vx

Question 53

biased estimator

Answer 53

The formula for the variance or standard deviation involving a final division by N, used to describe a sample, but that tends to underestimate the population variability

Question 54

unbiased estimator

Answer 54

The formula for the variance or standard deviation involving a final division by N- 1; calculated using sample data to estimate the population variability

Question 55

estimated population variance s^2vx

Answer 55

The unbiased estimate of the population variance calculated from sample data using N-1

Question 56

estimated popu. standard deviation

Answer 56

The unbiased estimate of the population standard deviation calculated from sample data using N- 1