Chapters 2,3,&4 Flashcards
Data
Systematically recorded information, whether numbers or labels, together with it’s context
Context
The context ideally tells Who was measured, What was measured, How the data were collected, Where the data were collected and When and Why the study was performed
Data table
An arrangement of data in which each row represents a case and each column represents a variable
Case
Individual about whom or which we have data
Variable
Holds info about the same characteristic for many cases
Categorical variable
Names categories (whether with words or numerals)
Quantitative variable
The numbers act as a numerical value- always have units
Unit
Quantity or amount adopted as a standard of measurement
Frequency table
Lists the categories in a categorical variable and gives the count or percentage
Distribution
Gives possible values of variable and the relative frequency of each value
Area principle
Each data value should be represented by the same amount of area
Bar chart
Show bars representing the count in each category in a categorical variable
Pie chart
Shows how a “whole” divides into categories
Contingency table
Displays counts and percentages of individuals into categories on 2 or more variables
Marginal distribution
The distribution of either variable alone- the totals found in the “margins” of the table
Conditional distribution
Restricting the Who to only consider a smaller group of individuals
Independence
If the conditional distribution of 1 variable is the same for each category
Simpsons Paradox
When the averages are taken across different groups, they can appear contradictory
Histogram
Adjacent bars to show the distribution of values in a quantitative variable
Stem & leaf plot
Shows quantitative data values in a way that sketches the distribution
Dot plot
Graphs a dot for each case
Shape
Single vs multiple modes
Symmetry vs skew ness
Outliers, clusters, gaps
Mode
Hump or high point of a shape
Unimodal
Shape of histogram when it is shaped like a mound. Bimodal is 2 mounds and multimodal is more than 2
Uniform
Distribution that is roughly flat
Symmetric
Distribution is about the same on either halve of the mode
Tails
Parts of a distribution that trail off to either side
Skewed
One tail stretches out further than the other
Outliers
Extreme values that do not appear to belong with the rest of the data
Time plot
Shows data that changes over time
