Heating fuel in buildings
Use this diagram to explain that when group sizes differ, it is easier to compare proportions within groups than the raw frequencies.
Select Propn within Year of construction to display all within-group proportions. Click any row to see standardisation process.
Note the low proportion of the oldest buildings heated by electricity and the high proportion heated by gas.
Select Percent within Year of construction to show the proportions as percentages. Without the leading zeros, it is easier to scan down columns to quickly spot unusual values.
The Cincinnati Gas and Electric Company conducted a survey of commercial buildings in 1992. The contingency table below describes the main heating fuel used in buildings of different ages.