Ch. 2 Pollocks Essentials Of Political Analysis

Front 1

variable

Back 1

An Empirical measurement of a characteristic.
(p. 26)

Front 2

Interval-Level variable

Back 2

* Communicates exact differences between units of analysis
* Example is Age measured in years
(p. 28)

Front 3

nominal-level variable

Back 3

* Communicates categorical differences between units of analysis on the characteristic being measured
* Example: Separating people into categories based on marital status, religious denomination.
(p. 28)

Front 4

ordinal-level variable

Back 4

* Communicates relative differences between units of analysis
* Example, ranking levels of support for a certain principle
(p. 28)

Front 5

Index

Back 5

Additive combination of ordinal variables
* Each identically coded
* All measure same concept
(p. 29)

Front 6

Likert scale

Back 6

Scale is additive index of 5-7 value ordinals
* each captures strength and direction of agreement or disagreement with a declared statement

* Conceived by Rensis Likert
(p. 29)

Front 7

Central Tendency

Back 7

* Typical or average value of a variable
* Can be measured in 3 ways
- Mode
- Median
- Mean
(p. 31)

Front 8

dispersion

Back 8

The variation or spread of cases across its values
(p. 31)

Front 9

mean

Back 9

* Closest to use of term "Average"
* Sum all cases values and divide by the number of cases
(p. 31)

Front 10

median

Back 10

* Value of variables that divides the cases down the middle
* for odd number of cases, it is central number when ordered
* for even number of cases, it is the average (mean) of the central two numbers
(p. 31)

Front 11

mode

Back 11

* most common value of a set
* largest number of cases exhibit that number
(p. 31)

Front 12

Frequency distribution

Back 12

* a tabular summary of a variables values
* First column depicts variables values
* Second column depicts variables raw frequency or number of individual units of analysis conforming to this variable
* Third column depicts percent of cases falling into each value
* In ordinal values, a fourth column depicts cumulative percentage.
(p. 32)

Front 13

raw frequency

Back 13

* number of individual units of analysis conforming to a specific value
* Second column on frequency distribution chart
(p. 32)

Front 14

Bar Chart

Back 14

A graphical display of data
* bars represent values
* Bar heights represent frequency or percentages
(p. 33)

Front 15

cumulative percentage

Back 15

* Percentage of cases at or below any given value of the variable
* Depicted in fourth column of a frequency distribution chart
(p. 33)

Front 16

total frequency

Back 16

* Sum of raw frequency
* reported at bottom of raw frequency column (column 2) on frequency distribution chart
(p. 33)

Front 17

Bimodal Distribution

Back 17

Frequency distribution with two different values that are heavily populated
* Two high bars on bar chart
(p. 34)

Front 18

percentile

Back 18

Reports the percentage of cases that 'lie below' a specified value
* Used in ordinal variables
* 80th percentile would mean 20% of cases were higher order and 80 percent were lower order
(p. 35)

Front 19

negative skew

Back 19

Distributions with longer, skinnier tail to the left-side of a chart
* Mean would be skewed downwards by outlier low answers
(p. 38)

Front 20

positive skew

Back 20

Distributions with longer, skinnier tail to the right-side of a chart
* Mean would be skewed upwards by outlier high answers
(p. 38)

Front 21

resistant measure of central tendency

Back 21

The Median
* sometimes more faithful to the true center of an interval level-variable
(p. 38)