Organizing Visualizing and Describing Data

Question 1

Absolute dispersion

Answer 1

The amount of variability present without comparison to any reference point or benchmark.

Question 2

Absolute frequency

Answer 2

The actual number of observations counted for each unique value of the variable (also called raw frequency).

Question 3

Arithmetic mean

Answer 3

The sum of the observations divided by the number of observations.

Question 4

Bar chart

Answer 4

A chart for plotting the frequency distribution of categorical data, where each bar represents a distinct category and each bar’s height is proportional to the frequency of the corresponding category. In technical analysis, a bar chart that plots four bits of data for each time interval—the high, low, opening, and closing prices. A vertical line connects the high and low prices. A cross-hatch left indicates the opening price and a cross-hatch right indicates the closing price.

Question 5

Bimodal

Answer 5

A distribution that has two most frequently occurring values.

Question 6

Box and whisker plot

Answer 6

A graphic for visualizing the dispersion of data across quartiles. It consists of a “box” with “whiskers” connected to the box.

Question 7

Bubble line chart

Answer 7

A line chart that uses varying-sized bubbles to represent a third dimension of the data. The bubbles are sometimes color-coded to present additional information.

Question 8

Categorical data

Answer 8

Values that describe a quality or characteristic of a group of observations and therefore can be used as labels to divide a dataset into groups to summarize and visualize (also called qualitative data).

Question 9

Chi-square test of independence

Answer 9

A statistical test for detecting a potential association between categorical variables.

Question 10

Clustered bar chart

Answer 10

A bar chart for showing joint frequencies for two categorical variables (also known as a clustered bar chart).

Question 11

Coefficient of variation

Answer 11

The ratio of a set of observations’ standard deviation to the observations’ mean value.

Question 12

Confusion matrix

Answer 12

A grid used for error analysis in classification problems, it presents values for four evaluation metrics including true positive (TP), false positive (FP), true negative (TN), and false negative (FN).

Question 13

Contingency table

Answer 13

A table of the frequency distribution of observations classified on the basis of two discrete variables.

Question 14

Continuous data

Answer 14

Data that can be measured and can take on any numerical value in a specified range of values.

Question 15

Correlation

Answer 15

A measure of the linear relationship between two random variables.

Question 16

Cost averaging

Answer 16

The periodic investment of a fixed amount of money.

Question 17

Cross-sectional data

Answer 17

A list of the observations of a specific variable from multiple observational units at a given point in time. The observational units can be individuals, groups, companies, trading markets, regions, etc.

Question 18

Cumulative absolute frequency

Answer 18

Cumulates (i.e., adds up) in a frequency distribution the absolute frequencies as one moves from the first bin to the last bin.

Question 19

Cumulative frequency distribution chart

Answer 19

A chart that plots either the cumulative absolute frequency or the cumulative relative frequency on the y-axis against the upper limit of the interval and allows one to see the number or the percentage of the observations that lie below a certain value.

Question 20

Cumulative relative frequency

Answer 20

A sequence of partial sums of the relative frequencies in a frequency distribution.

Question 21

Data

Answer 21

A collection of numbers, characters, words, and text—as well as images, audio, and video—in a raw or organized format to represent facts or information.

Question 22

Data table

Answer 22

see two-dimensional rectangular array.

Question 23

Deciles

Answer 23

Quantiles that divide a distribution into 10 equal parts.

Question 24

Descriptive statistics

Answer 24

The study of how data can be summarized effectively.

Question 25

Discrete data

Answer 25

Numerical values that result from a counting process; therefore, practically speaking, the data are limited to a finite number of values.

Question 26

Dispersion

Answer 26

The variability of a population or sample of observations around the central tendency.

Question 27

Downside risk

Answer 27

Risk of incurring returns below a specified value.

Question 28

Excess kurtosis

Answer 28

Degree of kurtosis (fatness of tails) relative to the kurtosis of the normal distribution.

Question 29

Fat-Tailed

Answer 29

Describes a distribution that has fatter tails than a normal distribution (also called leptokurtic).

Question 30

Fractile

Answer 30

A value at or below which a stated fraction of the data lies. Also called quantile.

Question 31

Frequency distribution

Answer 31

A tabular display of data constructed either by counting the observations of a variable by distinct values or groups or by tallying the values of a numerical variable into a set of numerically ordered bins (also called a one-way table).

Question 32

Frequency polygon

Answer 32

A graph of a frequency distribution obtained by drawing straight lines joining successive points representing the class frequencies.

Question 33

Geometric mean

Answer 33

A measure of central tendency computed by taking the nth root of the product of n non-negative values.

Question 34

Grouped bar chart

Answer 34

A bar chart for showing joint frequencies for two categorical variables (also known as a clustered bar chart).

Question 35

Harmonic mean

Answer 35

A type of weighted mean computed as the reciprocal of the arithmetic average of the reciprocals.

Question 36

Heat map

Answer 36

A type of graphic that organizes and summarizes data in a tabular format and represents it using a color spectrum.

Question 37

Histogram

Answer 37

A chart that presents the distribution of numerical data by using the height of a bar or column to represent the absolute frequency of each bin or interval in the distribution.

Question 38

Interquartile range

Answer 38

The difference between the third and first quartiles of a dataset.

Question 39

Interval

Answer 39

With reference to grouped data, a set of values within which an observation falls.

Question 40

Joint frequencies

Answer 40

The entry in the cells of the contingency table that represent the joining of one variable from a row and the other variable from a column to count observations.

Question 41

Leptokurtic

Answer 41

Describes a distribution that has fatter tails than a normal distribution (also called fat-tailed).

Question 42

Line chart

Answer 42

A type of graph used to visualize ordered observations. In technical analysis, a plot of price data, typically closing prices, with a line connecting the points.

Question 43

Linear interpolation

Answer 43

The estimation of an unknown value on the basis of two known values that bracket it, using a straight line between the two known values.

Question 44

Marginal frequencies

Answer 44

The sums determined by adding joint frequencies across rows or across columns in a contingency table.

Question 45

Mean absolute deviation

Answer 45

With reference to a sample, the mean of the absolute values of deviations from the sample mean.

Question 46

Measure of central tendency

Answer 46

A quantitative measure that specifies where data are centered.

Question 47

Measures of location

Answer 47

Quantitative measures that describe the location or distribution of data. They include not only measures of central tendency but also other measures, such as percentiles.

Question 48

Median

Answer 48

The value of the middle item of a set of items that has been sorted into ascending or descending order (i.e., the 50th percentile).

Question 49

Mesokurtic

Answer 49

Describes a distribution with kurtosis equal to that of the normal distribution, namely, kurtosis equal to three.

Question 50

Modal interval

Answer 50

With reference to grouped data, the interval containing the greatest number of observations (i.e., highest frequency).

Question 51

Mode

Answer 51

The most frequently occurring value in a distribution.

Question 52

Nominal data

Answer 52

Categorical values that are not amenable to being organized in a logical order. An example of nominal data is the classification of publicly listed stocks into sectors.

Question 53

Numerical data

Answer 53

Values that represent measured or counted quantities as a number. Also called quantitative data.

Question 54

Observation

Answer 54

The value of a specific variable collected at a point in time or over a specified period of time.

Question 55

One-dimensional array

Answer 55

The simplest format for representing a collection of data of the same data type.

Question 56

Ordinal data

Answer 56

Categorical values that can be logically ordered or ranked.

Question 57

Panel data

Answer 57

A mix of time-series and cross-sectional data that contains observations through time on characteristics of across multiple observational units.

Question 58

Percentiles

Answer 58

Quantiles that divide a distribution into 100 equal parts that sum to 100.

Question 59

Platykurtic

Answer 59

Describes a distribution that has relatively less weight in the tails than the normal distribution (also called thin-tailed).

Question 60

Population

Answer 60

All members of a specified group.

Question 61

Qualitative data

Answer 61

Values that describe a quality or characteristic of a group of observations and therefore can be used as labels to divide a dataset into groups to summarize and visualize (also called Categorical data).

Question 62

Quantile

Answer 62

A value at or below which a stated fraction of the data lies. Also referred to as a fractile.

Question 63

Quantitative data

Answer 63

Values that represent measured or counted quantities as a number. Also called Numerical data.

Question 64

Quartiles

Answer 64

Quantiles that divide a distribution into four equal parts. 25%iles

Question 65

Quintiles

Answer 65

Quantiles that divide a distribution into five equal parts. 20%iles

Question 66

Range

Answer 66

The difference between the maximum and minimum values in a dataset.

Question 67

Raw data

Answer 67

Data available in their original form as collected.

Question 68

Relative dispersion

Answer 68

The amount of dispersion relative to a reference value or benchmark.

Question 69

Relative frequency

Answer 69

The absolute frequency of each unique value of the variable divided by the total number of observations of the variable.

Question 70

Sample

Answer 70

A subset of a population.

Question 71

Sample correlation coefficient

Answer 71

A standardized measure of how two variables in a sample move together. It is the ratio of the sample covariance to the product of the two variables' standard deviations.

Question 72

Sample covariance

Answer 72

A measure of how two variables in a sample move together.

Question 73

Sample excess kurtosis

Answer 73

A sample measure of the degree of a distribution's kurtosis in excess of the normal distribution's kurtosis.

Question 74

Sample mean

Answer 74

The sum of the sample observations divided by the sample size.

Question 75

Sample skewness

Answer 75

A sample measure of the degree of asymmetry of a distribution.

Question 76

Sample standard deviation

Answer 76

The positive square root of the sample variance.

Question 77

Sample statistic

Answer 77

A quantity computed from or used to describe a sample.

Question 78

Sample variance

Answer 78

The sum of squared deviations around the mean divided by the degrees of freedom.

Question 79

Scatter plot matrix

Answer 79

A tool for organizing scatter plots between pairs of variables, making it easy to inspect all pairwise relationships in one combined visual.

Question 80

Skewed

Answer 80

Not symmetrical.

Question 81

Spurious correlation

Answer 81

Refers to: 1) correlation between two variables that reflects chance relationships in a particular dataset; 2) correlation induced by a calculation that mixes each of two variables with a third variable; and 3) correlation between two variables arising not from a direct relation between them but from their relation to a third variable.

Question 82

Stacked bar chart

Answer 82

An alternative form for presenting the frequency distribution of two categorical variables, where bars representing the sub-groups are placed on top of each other to form a single bar. Each sub-section is shown in a different color to represent the contribution of each sub-group, and the overall height of the stacked bar represents the marginal frequency for the category.

Question 83

Standard deviation

Answer 83

The positive square root of the variance; a measure of dispersion in the same units as the original data.

Question 84

Statistic

Answer 84

A summary measure of a sample of observations.

Question 85

Structured data

Answer 85

Data that are highly organized in a pre-defined manner, usually with repeating patterns.

Question 86

Tag cloud / Word Cloud

Answer 86

A visual device for representing textual data, which consists of words extracted from a source of textual data. The size of each distinct word is proportional to the frequency with which it appears in the given text (also known as Word cloud).

Question 87

Target semi-deviation/ Target downside deviation

Answer 87

A measure of downside risk, calculated as the square root of the average of the squared deviations of observations below the target (also called target downside deviation).

Question 87

Thin-Tailed

Answer 87

Describes a distribution that has relatively less weight in the tails than the normal distribution (also called platykurtic)1

Question 88

Time-series data

Answer 88

A sequence of observations for a single observational unit of a specific variable collected over time and at discrete and typically equally spaced intervals of time (such as daily, weekly, monthly, annually, or quarterly).

Question 89

Tree-Map

Answer 89

Another graphical tool for displaying categorical data. It consists of a set of colored rectangles to represent distinct groups, and the area of each rectangle is proportional to the value of the corresponding group.

Question 90

Trimmed mean

Answer 90

A mean computed after excluding a stated small percentage of the lowest and highest observations.

Question 91

Trimodal

Answer 91

A distribution that has the three most frequently occurring values.

Question 92

Two-dimensional rectangular array

Answer 92

A popular form for organizing data for processing by computers or for presenting data visually. It is comprised of columns and rows to hold multiple variables and multiple observations, respectively (also called a data table).

Question 93

Unimodal

Answer 93

A distribution with a single value that is most frequently occurring.

Question 94

Unstructured data

Answer 94

Data that do not follow any conventionally organized forms.

Question 95

Variable

Answer 95

A characteristic or quantity that can be measured, counted, or categorized and that is subject to change (also called a field, an attribute, or a feature).

Question 96

Variance

Answer 96

The expected value (the probability-weighted average) of squared deviations from a random variable's expected value.

Question 97

Visualization

Answer 97

The presentation of data in a pictorial or graphical format for the purpose of increasing understanding and for gaining insights into the data.

Question 98

Weighted mean

Answer 98

An average in which each observation is weighted by an index of its relative importance.

Question 99

Winsorized mean

Answer 99

A mean computed after assigning a stated percentage of the lowest values equal to one specified low value and a stated percentage of the highest values equal to one specified high value.

Question 100

Word cloud

Answer 100

A visual device for representing textual data, which consists of words extracted from a source of textual data. The size of each distinct word is proportional to the frequency with which it appears in the given text (also known as tag cloud).