A large study was conducted to test the effectiveness of a drug in combination with aspirin in warding off heart attacks and strokes. The trial involved more than 12,000people 45 years of age or older from 32 countries, including the United States, who had been diagnosed with cardiovascular disease or had multiple risk factors. The subjects were randomly assigned to one of two groups. After 2 years, there was no difference in the risk of heart attack, stroke, or dying from heart disease between those who took the prescription drug and low-dose aspirin daily and those who took low-dose aspirin plus a dummy pill. The 2-drug combination actually increased the risk of dying (5.6% versus 3.4%) or dying specifically from cardiovascular disease (3.1% versus 2.3%).
No Sample sizes were given about the study: however, let us assume that the sample sizes for each group were
n1 = 6220 and n2 = 5780. Determine whether the risk of dying was significantly different for the two groups. use alpha = 0.01
Test Statistic: z= ________ (Round answer to two decimal places)