Chapter 1: Exploring data

Question 1

Individuals

Answer 1

Individuals are the objects described by a set of data

Question 2

Variable

Answer 2

an attribute that describes a person, place, thing, or idea

Question 3

Categorial Variable

Answer 3

categorical variables take on values that are names or labels

Question 4

Quantitative Variable

Answer 4

quantitative variables are numerical

Question 5

Continuous

Answer 5

continuous distribution is one in which data can take on any value within a specified range

Question 6

Univariate Data

Answer 6

a study that looks at only one variable

Question 7

Bivariate Data

Answer 7

a study that examines the relationship between two variables

Question 8

Population

Answer 8

population refers to the total set of observations that can be made

Question 9

Sample

Answer 9

a sample refers to a set of observations drawn from a population

Question 10

Census

Answer 10

a study that obtains data from every member of a population

Question 11

Distribution

Answer 11

The distribution of a statistical data set (or a population) is a listing or function showing all the possible values

Question 12

Inference

Answer 12

inference is the process of using data analysis to deduce properties of an underlying distribution of probability

Question 13

Frequency Table

Answer 13

when a table shows frequency counts for a categorical variable, it is called a frequency table

Question 14

Relative Frequency

Answer 14

Relative frequency = Subgroup count / Total count

Question 15

Table

Answer 15

tables showing the values of the cumulative distribution functions, probability functions, or probability

Question 16

Roundoff Error

Answer 16

the difference between an approximation of a number used in computation and its exact (correct) value

Question 17

Pie Chart

Answer 17

a circular statistical graphic, which is divided into slices to illustrate numerical proportion

Question 18

Bar Graph

Answer 18

a chart that plots data using rectangular bars or columns

Question 19

Two-way Table

Answer 19

a statistical table that shows the observed number or frequency for two variables

Question 20

Marginal Distribution

Answer 20

marginal distribution is the percentages out of totals

Question 21

Conditional

Answer 21

conditional distribution is the percentages out of some column

Question 22

Segmented Bar Graph

Answer 22

a bar graph with two columns. one of them shows a discrete value (i.e. numbers) while the other one compares the values with different bars in different categories

Question 23

Side-by-side Bar Graph

Answer 23

the bars are split into colored bar segments

Question 24

Association

Answer 24

any relationship between two measured quantities that renders them statistically dependent

Question 25

Simpson’s Paradox

Answer 25

when we combine all of the groups together and look at the data in aggregate form, the correlation that we noticed before may reverse itself

Question 26

Dot Plot

Answer 26

a graph for displaying the distribution of numerical variables where each dot represents a value

Question 27

Shape

Answer 27

symmetric, how many peaks it has, if it is skewed to the left or right, and whether it is uniform

Question 28

Mode

Answer 28

a number that appears the most amount of times in a set of data

Question 29

Center

Answer 29

mean or median of the data

Question 30

Spread

Answer 30

how similar or varied the set of observed values are for a particular variable (data item)

Question 31

Range

Answer 31

a simple measure of variation in a set of random variables

Question 32

Outlier

Answer 32

a data point that diverges greatly from the overall pattern of data is called an outlier

Question 33

Symmetric

Answer 33

a symmetric distribution can be divided at the center so that each half is a mirror image of the other

Question 34

Skewed Right

Answer 34

fewer observations on the right (toward higher values) are said to be skewed right

Question 35

Skewed Left

Answer 35

fewer observations on the left (toward lower values) are said to be skewed left

Question 36

Unimodal

Answer 36

distributions with one clear peak are called unimodal

Question 37

Bimodal

Answer 37

distributions with two clear peaks are called bimodal

Question 38

Multimodal

Answer 38

a probability distribution with more than one peak, or “mode”

Question 39

Stemplot

Answer 39

the entries on the left are called stems; and the entries on the right are called leaves

Question 40

Splitting Stems

Answer 40

stem-and-leaf plots that have more than 1 space on the stem for the same interval

Question 41

Back-to-back Stem

Answer 41

back-to-back stem plots are a graphic option for comparing data from two populations

Question 42

Plots

Answer 42

a graphical technique for representing a data set, usually as a graph showing the relationship between two or more variables

Question 43

Histogram

Answer 43

columns are positioned over a label that represents a continuous, quantitative variable, and the height of the column indicates the size of the group defined by the column label

Question 44

Mean

Answer 44

the average of the data

Question 45

Median

Answer 45

the middle of all the data points collected

Question 46

Interquartile Range

Answer 46

a measure of variability, based on dividing a data set into quartiles

Question 47

Five-number

Answer 47

gives information about the location (from the median), spread (from the quartiles) and range (from the sample minimum and maximum) of the observations

Question 48

Summary

Answer 48

A summary is a brief statement or restatement of main points

Question 49

Boxplot

Answer 49

a type of graph used to display patterns of quantitative data

Question 50

Standard deviation

Answer 50

a numerical value used to indicate how widely individuals in a group vary

Question 51

Variance

Answer 51

a numerical value used to indicate how widely individuals in a group vary