Self-study
Support Government statistics show that the real (adjusted for inflation) average income for families has risen over the last five years. ██████████ █████ ████ ████ ███ ████████ ████████ ██████ ██ ███████ ███ █████████ ███ ████████ ████ ██████ ████ ████ █████████ ████ ███ ████ ████ ██████
Summarize Argument
The author concludes that the Andersen family’s real income must have increased over the last 5 years. This is based on the fact that the real average income for families has risen over the last five years, and this year the Andersen family’s income is average for families.
Identify and Describe Flaw
The author overlooks the possibility that the Andersen family’s income hasn’t changed in five years. Although they are at the average for family’s this year, that doesn’t mean they experienced an increase in income from previous years. They might have been above average in previous years, and the nation’s average income for families has simply caught up to their income.
13.
The reasoning in the argument ██ ████ ██████████ ██ █████████ ██ ███ ███████ ████ ███ ████████
a
ambiguously uses the ████ █████████ ██ ███ █████████ ██████
“Average” in “average income for families” means the same thing as “average” in “income is average for families.” It refers to the figure taken by adding up the total income for all families and dividing the figure by the number of families.
b
fails to take ████ ███████ █████████ ████ ███████ ██ ███ ████████ ████████ ██████
The argument concerns “real” income, which is defined as income that is “adjusted for inflation.” So the argument already takes into account inflation.
c
overlooks the possibility ████ ████ █████████ ███████ ███ █████ ███████
This possibility doesn’t undermine the argument, because the author never assumed that most families incomes are not below average. The argument is based on the average income for families. Reliance on that average doesn’t imply a belief about “most” families’ income.
d
fails to consider ███ ███████████ ████ ███ ████████ ████████ ████ ██████ ███ █████ ███████ ██ ███ ██████ ████
This shows why the Andersens’ income might not have increased. They are at the average for today, but that doesn’t imply they had a lower income in the past. They might have been above average in the past, and the average income has increased to their level.
e
presumes, without providing ██████████████ ████ ███ ██████████ █████ ██ ██████ ██ █████████ ████████ █████████ ██ ██████ ██████
The author doesn’t assume that the government never makes errors in gathering estimates for family income. Maybe, for example, the data for one family was reported incorrectly. That wouldn’t necessarily have significant impacts on the overall average income calculation.