For each of the following studies, give the parameter of interest and state any assumptions that are necessary for the inferences to be valid.

a. Human Factors (December 2015) published a study on how well firefighter gloves fit. One objective was to compare the proportions of gloves that fit well for males and females. From data collected for 586 firefighters (546 males and 40 females), the researchers determined that 93% of males owned gloves that fit well, as compared to 49% of females a difference of 44%.

b. The results of an investigation of publicity on demand for anticholesterol drugs were reported in Marketing Science (January-February 2016). For each sampled month, the researchers measured the number of medical journal pages used for advertising the drugs Crestor (39 months) and Mevacor (142 months). They found that Crestor had a much higher average number of pages per month than Mevacor.

c. According to University of Florida News (April 11, 2001), feeding chickens corn oil causes them to produce larger eggs. In the study, the weight of eggs produced by each of a sample of chickens was recorded under two conditions: (1) while the chickens were on a regular diet and (2) while the chickens were on a diet supplemented by corn oil. The mean weight of the eggs produced with corn oil was 3 grams heavier than the mean weight produced with the regular diet.

d. A study in Behavioral Research in Accounting (July 2015) looked at how complicit an entry-level accountant is in carrying out an unethical request. After asking the subjects to perform what is clearly an unethical task (e.g., to bribe a customer), the researchers measured each subject’s intention to comply with the unethical request score. One aspect of the study focused on whether the variability in the scores differed depending on the subject’s impulsivity level (high or low).