Variable that describes data using words or numerals as labels
Categorical
Variable that describes data using numbers as numerical values
quantitative
The possible values of the variable and the relative frequency of each value
distribution
In a two-way table, the distribution of either variable alone
marginal
Distribution of a variable when considering only a smaller group of individuals
conditional
Table that lists the categories of a variable and gives the proportion of observations for each category
relative frequency
Shows a bar representing the count of each category in a categorical variable
barchart
Shows how a "whole" divides into categories by showing a wedge of a circle whose area corresponds to the proportion in each category
piechart
Shows bars divided proportionally into segments corresponding to the percentage in each group
segmentedbarchart
When a distribution is not symmetric and one tail stretches out farther than the other
skewed
Distribution with two modes
bimodal
Uses adjacent bars to show the distribution of values in a quantitative variable, where each bar represents the number of values falling in an interval
histogram
A numerical summary of how tightly the values are clustered around the "center"
spread
A distribution roughly flat in shape
uniform
Distributions with more than two modes
multimodal
Shape where the two halves on either side of the center look approximately like mirror images of each other
symmetric
Shape where the longer tail stretches to the right
skewedright
Type of display that shows quantitative data values in a way that shows the shape of the distribution in addition to individual data values
stemplot
Shape where the longer tail stretches to the left
skewedleft
Having one mode
unimodal
Graphs a dot for each case against a single axis
dotplot
Reveals single vs. multiple modes and symmetric vs. skewness
curve
a value that summarizes the entire distribution with a single number, a "typical" value
center
Tells how many standard deviations a value is from the mean
zscore
Numerical attribute of a population
parameter
In a Normal Model, about 68% of the values fall within 1 standard deviation of the mean, about 95% within 2 standard deviations, and about 99.7% within 3 standard deviations
empirical rule
The value found by subtracting the mean and dividing by the standard deviation
standardized score
Type of Normal model with mean 0 and standard deviation 1
standard normal
Numerical attribute of a set of data
statistic
The number that falls above a given % of the data
percentile
Displays the 5-number summary as a central box with the whiskers that extend to the non-outlying data values
boxplot
Minimum, 1st quartile, Median, 3rd quartile, Maximum
fivenumbersummary
Found by summing all the data values and dividing by the count
mean
The difference between the first and third quartiles
interquartilerange
The square root of the variance
standarddeviation
The value with a quarter of the data below it
firstquartile
Value more than 1.5 times the IQR below Q1 or above Q3
outlier
Difference between the maximum and minimum value
range
The value with a quarter of the data above it
thirdquartile
The middle value of a distribution with half the data above and half below it
median