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. \( \square \) The \( \qquad \) is men aged 50 to 84 . \( \square \) The \( \qquad \) is the 400 men who participated. This is a \( \qquad \) controlled experiment. The group of men who 1. population 2. sample 3. placebo 4. controlled 5. blind

Let's analyze the statements and match them with the appropriate terms. 1. **The \( \qquad \) is men aged 50 to 84.** - This refers to the entire group of individuals that the researchers are interested in studying. In this case, it is the broader group from which the sample is drawn. Therefore, the correct term is **population**. 2. **The \( \qquad \) is the 400 men who participated.** - This refers to the specific group of individuals that were actually recruited for the study. This is a subset of the population. Therefore, the correct term is **sample**. 3. **This is a \( \qquad \) controlled experiment.** - Since the study involves two groups (one taking aspirin and the other taking a placebo) and the participants do not know which group they are in, it is a controlled experiment. The correct term here is **controlled**. 4. **The group of men who** - The term that fits here is **placebo**, as it refers to the group that is taking the placebo instead of the actual treatment (aspirin). 5. **The study is designed so that participants do not know whether they are taking aspirin or the placebo. This is referred to as a \( \qquad \) study.** - The correct term for this is **blind**, as it indicates that the participants are unaware of which treatment they are receiving. Now, let's fill in the blanks: - The **population** is men aged 50 to 84. - The **sample** is the 400 men who participated. - This is a **controlled** experiment. - The group of men who take the **placebo**. - The study is a **blind** study. So the final matches are: 1. The **population** is men aged 50 to 84. 2. The **sample** is the 400 men who participated. 3. This is a **controlled** experiment. 4. The group of men who take the **placebo**. 5. The study is a **blind** study.