Measurement Scales (5 of 6)

No Distraction

Distraction

5yr
10yr

6
12

3
8

It looks as though the 10year olds are more distractible since distraction
cost them 4 points but only cost the 5year olds 3 points. However, it
might be that a change from 3 to 6 represents a larger difference than
a change from 8 to 12. Consider that the performance of 5year olds dropped
50% from distraction but the performance of 10year olds dropped only
33%.
Which age group is "really" more distractible? Unfortunately, there
is no clearly right or wrong answer. If proportional change is considered,
then 5year olds are more distractible; if the amount of change is considered
then 10year olds are more distractible. Keep in mind that statistical conclusions
are not affected by the choice of measurement scale even though the allimportant
interpretation of these conclusions can be.