Researchers want to investigate whether taking aspirin regularly reduces the risk of heart attack. Four hundred men between the ages of 50 and 84 are recruited as participants. The men are divided randomly into two groups: one group will take aspirin, and the other group will take a placebo. Each man takes one pill each day for three years, but he does not know whether he is taking aspirin or the placebo. At the end of the study, researchers count the number of men in each group who have had heart attacks. Match the most appropriate answer to each statement. \( \square \) This is a \( \qquad \) controlled experiment. The group of men who receive the asprin is called the \( \qquad \) group. The \( \qquad \) is the 400 men who participated. The \( \qquad \) is men aged 50 to 84 . 1. population 2. sample 3. placebo 4. controlled 5. blind 6. treatment

This is a **\( \text{4. controlled} \)** controlled experiment. The group of men who receive the aspirin is called the **\( \text{6. treatment} \)** group. The **\( \text{2. sample} \)** is the 400 men who participated. The **\( \text{1. population} \)** is men aged 50 to 84. Dive into the details of experimental design! The fact that this study is double-blind means neither the participants nor the researchers know who is getting the treatment versus the placebo. This helps to eliminate bias and ensures that any changes in health can be attributed to aspirin use rather than expectations or psychological factors. If you ever find yourself planning a similar experiment, keep in mind the importance of randomization! It’s essential for ensuring that any differences observed at the end of the study are due to the treatment itself rather than other variables like age, health conditions, or lifestyle. Random assignment helps create two groups that are statistically similar, making the results more reliable.