Identify the level of measurement used: Nominal, Ordinal,
Interval or Ratio
a) Blood lead levels of low, medium and high are used to
categorize subjects in a study.
b) Researchers measure body temperature in $^\circ$C.
c) A study about hospital births organizes data by
hospital. The categories are: Health Sciences North, North Bay
Regional Health Centre and Sault Area Hospital.
d) Researchers measure income in dollars.