after studying vitamin supplements for many decades, researchers still cannot determine whether vitamin supplements actually improve health. nature magazine published an article in june 2014 titled "nutrition: vitamins on trial" analyzing the results of different research studies.

which of the following research scenarios does not describe a comparison that is appropriate for testing a hypothesis about the difference in two population proportions?

of more economically developed countries andc itizens of less economically dew eloped countries es measuring the percentage of the population with disease from nutritional deficiencies a simple random survey of us. citizens comparing the percent of us. citizens who take daily vitamin s and the percent of us citizens who do not take vitamins a double-blind, placebo-controlled clinical trial measuring the percent of women over age 50 with low vitamin b12 levels.