For the article below, what are the independent, dependent, mediating and moderator variables? What is the claim that the author is making? Is this research design an experiment? Why or why not? What are various levels of measurement in you would use as a researcher in this article's research? Please provide an example for each by using the article below.

Would you agree with the following statement: The researchers used a random assignment sampling method. Yes or no, and how so? What are the threats to internal validity in this case? Clearly explain what each means, how and if it applies.

Do men produce the worst flatus?

For years, scientists have been studying men and women's farts in an effort to better understand the digestive process. In one study, researchers asked participants to record the smell, and texture of their farts for a period of seven days. The results were surprising. In 1998 there was a study done that tried to clarify what was contained in flatulence and what the difference was between men and women. Normally, we assume that men produce the more 'deadlier' farts than women. It revealed that while men fart more wind on average than women, it was the females that had a higher concentration of Hydrogen sulphide, which is the ingredient that makes your farts, well, stink. Or in our household, fall in to the 'dangerous' category. According to a new study, the smell of a man's fart is more likely to smell fruity, while a woman's fart is more likely to smell earthy.

But the best part about all of this? How they got the samples by putting participants in closed classrooms divided by gender: some loose people out there had to literally smell people's farts and get some readings on them. The participants were also made sure that both rooms were exactly 20 degrees Celsius throughout this research, and each room had its own bathroom. Also, the participants were only told that this research was about digestion, and nothing more.

The study, which was conducted by the University of Exeter, involved asking participants to smell farts from both men and women and then rate them on a scale of 1 to 7, with 1 being the smelliest and 7 being the least smelly. The judges were not aware they were smelling human flatus and the results showed that words used to describe the smells were "rotten eggs," "decomposing vegetables" and "sweet." When it came to specific smells, men's farts were more likely to smell fruity, while women's farts were more likely to smell earthy. So, why do men's and women's farts smell different? The researchers say it's because of the different bacteria that live in men's and women's guts. "The different types of bacteria that live in men and women's guts could be causing the different smells," said Dr. Clare Collins, a co-author of the study. "We know that men and women have different gut bacteria because of the different diets that they eat. Men tend to eat more meat and women tend to eat more fruits and vegetables."

The results showed that, on average, men's farts were rated as 2.5, while women's farts were rated as 4.2. After all of the results were collected, it was concluded that "the flatus of women had a significantly higher concentration of hydrogen sulphide and a greater odour intensity than did that of men."