A group of subjects was given a food frequency questionnaire to assess how many times per week or month they consume alcohol. A fasting blood sample was taken and the blood cholesterol level was determined. It was found that the higher the frequency of alcohol consumption, the lower the cholesterol level. What type of study is described here ?
举一反三
- Generally speaking, the higher the sound quality is required, the higher the quantization level and the lower the sampling frequency is.
- Generally speaking, the higher the sound quality is required, the higher the quantization level and the lower the sampling frequency is. A: 正确 B: 错误
- 49（） A: Second, I could lower my blood cholesterol level simply by changing what I ate. B: I was three years old at that time. C: There is not enough oxygen in the blood. D: It was a heart attack just waiting to happen E: The trial was designed to test the effect of lowering blood cholesterol on the risk of heart disease. F: The death rate for the test was only 1 in 100, I was assured.
- A psychologist studied the effect of blood alcohol on driving behavior. In this study the driving behavior was the _________ variable.
- All of the following are the well-established modifiable risk factors of coronary heart disease EXCEPT () A: Cigarette smoking B: Drinking beverages C: High blood pressure D: Elevated Serum Cholesterol level