The results of a study8 suggest that the initial electrocardiogram (ECG) of a suspected heart attack victim can be used to predict in-hospital complications of an acute nature. The study included 469 patients with suspected myocardial infarction (heart attack). Each patient was categorized according to whether their initial ECG was positive or negative and whether the person suffered life-threatening complications subsequently in the hospital. The results are summarized in the following table.
Subsequent In-Hospital Life- Threatening Complications
|
ECG
|
No
|
Yes
|
Total
|
|
Negative
|
166
|
I
|
167
|
|
Positive
|
260
|
42
|
302
|
|
Total
|
426
|
43
|
469
|
a. Is there sufficient evidence to indicate that whether or not a heart attack patient suffers complications depends on the outcome of the initial ECG? Test using α = .05.
b. Give bounds for the observed significance level.