Coursera Basic Statistics
Notes from Coursera Basic Statistics.
Data and visualization
Descriptive Statistics?
Variables - characteristics of something or someone Cases - the something of someone being measured Observation - a variable meausurement for a particular case
Levels of Measurement
Categorical
Nominal - There’s some difference the values, e.g. City of Birth Ordinal - Values can be ordered, e.g. 1st, 2nd place
Quantitative
Interval - Values have intervals, e.g. Age Ratio - Value has meaningful zero point, e.g. Height
Ways to present data
Data matrix - a matrix with cases on the y-axis and variables on the x-axis. Values within the matrix are observations, e.g:
Person | Age | Weight | Eye Color |
---|---|---|---|
Bob | 42 | 210 | Blue |
Alice | 24 | 120 | Brown |
Frequency Table - One way to summarize data matrix, e.g.:
Eye Color | Percent |
---|---|
Blue | 14 |
Brown | 28 |
Charts
Pie Chart or Bar Graph for categorical data Dot Plot or Histogram for quantitative