A study is conducted to see if diet has any effect on blood pressure. Four groups of 10 women each are given four kinds of diets. After 4 months, the blood pressures of groups are compared.
I. Determine the population?
II. What is the sample?
III. Is the study observational or experimental? Justify your answer.
IV. What are the variables?
V. For each of those variables, what level of measurement (nominal, ordinal, interval, or ratio) was used to obtain data from these variables?