a research analyst for the city fire department suspects tha
a research analyst for the city fire department, suspects that old water pumps are more likely to fail. From the data in the accompanying table, construct a contingency table and check Drant’s suspicion. How else could this problem be analyzed? (Hint: The sub-categories of “age of pump” can be “less than 30 years” and “30 years over”; the sub-categories of “pump performance” can be “pump failed” and “pump did not failed” as indicated by the problem. Organize the data and build a contingency table according to these subcategories and then analyze.)
| Pump Failed | Pump Did not Fail | Pump Did not Fail | 
| 23 | 15 | 7 | 
| 47 | 6 | 9 | 
| 11 | 9 | 4 | 
| 53 | 33 | 19 | 
| 26 | 26 | 36 | 
| 15 | 17 | 47 | 
| 42 | 9 | 31 | 
| 37 | 12 | 23 | 
| 31 | 6 | |
| 46 | 9 | |
| 15 | 3 | 
Solution

