Describing Distributions Flashcards
What are the 4 requirements for describing a distribution?
Center, Shape, Spread, Outliers
Center
Mean, Median or Mode
Measures of Spread
How far apart the numbers are in relation to each other
Range, IQR, Variance and Standard Deviation
Shape
Symmetric, normal, skewed left, skewed right, uniform, bimodal
Box Plot
A graph of the 5 number summary
A modified box plot shows if the data set has outliers.
Stemplot
A graph for quantitative data. Each value of the data set is represented by a stem and a leaf. Each leaf may only be 1 digit. Stem plots may have rounded values in place of the actual data.
Histogram
Common distribution for one variable
Dot Plot
A simple graph for small data sets
Mean
Average
Median
The middle number in a data set when the numbers are in order.
Sometimes called Q2 or MED
Mode
Most common value within the data
Outliers
A value that doesnt follow the general trend of the data.
Upper limit = Q3 + 1.5(IQR)
Lower limit = Q1 - 1.5(IQR)
Standard Deviation
A measure of spread. The average distance from the mean.
Range
A measure of spread
Maximum-Minimum
5 Number Summary
Used in box plots
Min-Q1-Median-Q3-Max
Quantitative
Numerical measures (order)
Qualitative
Classification of individuals based on attributes/characteristics (categorical, grouping)
Bar Graph
Used for categorical data
Ogive
A relative cumulative frequency histogram
Pie Chart
Categorical data separated into percentages
Symmetric
Equal on both sides
Minimum
Smallest value within the data
Q3
The median between the median and the maximum
Time Plot
Used to follow trends based on time (connecting)
Q1
Median between the minimum and median
Normal
Perfectly symmetric distribution
Uniform
Histogram with bars of all the same height
Bi-Modal
A graph with 2-peaks
Maximum
Largest value in the data set
Population
Entire group of individuals to be studied
Sample
Subset of studied population
