In a study by British researchers who were interested in learning about the rela
ID: 3206644 • Letter: I
Question
In a study by British researchers who were interested in learning about the relationship between diet and the rate of having a second heart attack amongst the thousands of British females who were first-time heart attack victims, 720 British female heart attack victims were randomly chosen and then each was randomly assigned to one of two different carefully-controlled diet regimens; every meal for six months was prepared for them by nutritionists. The researchers recorded “Yes” if the participant in the study had one or more heart attacks during the six-month period and they recorded “No” if she didn’t. The 360 heart attack victims who ate the Mediter- ranean diet had a significantly lower rate of having a second heart attack than the 360 randomly selected heart attack victims who ate the Western diet. Address parts (a) and (b).
(a) Is this study an observational study or an experiment? Explain.
(b) Use a complete English sentence to carefully, clearly and completely describe each of the following in this study:
1)the population of interest to these researchers
2) the explanatory variable.
3) the response variable.
Explanation / Answer
(a)observational study
This type of research draws a conclusion by comparing subjects against a control group, in cases where the researcher has no control over the experiment. A research study comparing the risk of developing lung cancer, between smokers and non-smokers, heart attack would be a good example of anobservational study.
(b)(1) British female heart attack victims, are the population of interest to these researcherse.
here we want to given inference about female heart attack victims based on sample, so it is population of interest
(2) here explanatory variable is diet regimens
An explanatory variable is any factor that can influence the response variable.
(2) response variable is number of second heart attack
A response variable is the particular quantity that we ask a question about in our study.