EXAMPLE 26 Determining independence using the alternative method
We return to the direct mail marketing data from Example 19, reproduced here in Table 23. Use the alternative method for determining independence to determine whether the following two events are independent:
Response | Credit card on file? | ||
---|---|---|---|
No | Yes | Total | |
Did not respond | 161 | 79 | 240 |
Did respond | 17 | 31 | 48 |
Total | 178 | 110 | 288 |
Solution
Using Table 23, we may find the following probabilities:
Because , we have ; therefore, and are dependent.
NOW YOU CAN DO
Exercises 79–84.