Question

"Freshman 15": Fact or Fantasy? BOSTON Along with all of the typical "back-to-school" hype about lunch boxes and school buses, each September is typically greeted with media reports and advice about the "freshman 15," which is the popular name given to the phenomenon of first-year college students gaining 15 pounds during their freshman year. But does this 15 pound weight gain actually occur, or is it simply a myth? Carole Nhu'y Hodge, Linda Jackson, and Linda Sullivan are Michigan State University researchers who conducted their own investigation. They studied 61 Michigan State female students who took an introductory psychology course. The volunteers, who were given extra credit for participation in the experiment, were weighed at the beginning of their freshman year and at a point in time six month later. Among their findings reported in Psychology of Women Quarterly : "Body weight at the beginning of the first college year (Time 1) was compared with weight approximately 6 months later (Time 2). Average weight at Time 2, 131.45 lb (59.62 kg), was no different from average weight at Time 1, 130.57 lb (59.23 kg)." They also state that "Our findings suggest it (the 15-lb weight gain)is fantasy, although additional research is needed before drawing firm conclusions."

The Assignment:

Answer the following:

1. What do the researchers infer when they say that there is "no difference" between the mean weight at Time 1 (130.57 lb) and the mean weight at Time 2 (131.45lb), when there is an apparent difference of 0.88-lb?
2. What are the limitations of this particular study? That is, if the sample data are used to make inferences about a population, identify the specific population in question.
3. Identify any aspects of the experiment that could potentially threaten the validity of the results.
4. Identify a possible null hypothesis and alternative hypothesis for this experiment.
5. Your submission is to be a well-written grammatically correct response.

Answer 1

When they say that there is "no difference" between the mean weight at Time 1 (130.57 lb) and the mean weight at Time 2 (131.45lb), the researchers infer that the difference of 0.88-lb is not significant but it is only by chance alone. ​​​​​​

Limitations:

The population of interest is all the first year students at college in the United States. But the sample is of only female students of only one course (introductory psychology) of only one state. So, the sample does not represent the population and is confined to a very small part of the population. Another aspect of the experiment that could potentially threaten the validity of the results is that the sample is voluntary and results in voluntary response bias. The female students who voluntarily participated in the experiment might have taken care of their weight and so, they might not have gain weight because they know that they are participating and have knowledge of the experiment.

Possible Null Hypothesis(H0):

Possible Alternative Hypothesis(H1):

( =Population mean, i.e., mean weight of all Michigan State female students of introductory psychology course at time 2; =Population mean, i.e., mean weight of all Michigan State female students of introductory psychology course at time 1).

These are the possible hypotheses for the given study and do not represent the actual population of interest of all the first year students of the nation.

Thus, the results of the given study are not valid and not at all reliable.