Common Core: S-ID.5
Problem 9 of 45s12-009
Of 80 students with a part-time job, 24 often feel rushed in the morning. Of 120 students without a job, 30 often feel rushed. Which statement do the relative frequencies support?
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Solution walkthrough1:58
- Put the counts in a two-way table: job or no job down the side, rushed or not across the top.
- Joint: one cell over all 200, . Marginal: a total over 200, .
- To compare groups, divide within each row: of job holders, of the rest.
- : the rates differ, so the variables are associated. Job holders are more likely to feel rushed.
- Traps: vs. divide by all 200, divides by the rushed column, and vs. are raw counts.