BALA201 LECTURE NOTES
Topic 3
Descriptive statistics
Descriptive statistics refers to methods of describing and summarising data using
tabular, visual and quantitative techniques.
Metrics and data classifications:
Metric  "a unit of measurement that provides a way to objectively quantify
performance".
Measurement  the act of obtaining data associated with a metric.
Measures  numerical values associated with a metric.
Metrics can be DISCRETE or CONTINOUS

Discrete: from counting something e.g., number of errors

Continuous: on a continuous scale e.g., length, weight
Data classifications (measurement scales)
categorical (
nominal
) data  sorted into categories according to specified characteristics.
ordinal data
 can be ordered or ranked.
interval data
 ordered, with constant differences between observations and many have
arbitrary zero points.
ratio data
 continuous and have a natural zero.
Scaling e.g.
Nominal  numbers assigned to runners.
Ordinal  rank order of winners
Interval  performance rating on a 010 scale
Ratio  time to finish in seconds.