Final answer:
The parameter of interest is the 'population proportion.' It represents the true percentage of men and women in the entire population who want to remain at their current weight, and it is used to compare these proportions between the two groups.
Step-by-step explanation:
The parameter of interest for testing whether the proportion of men wanting to stay at their current weight is different from the proportion of women wanting to stay at their current weight is the population proportion. This is because we are dealing with categorical data (wanting to stay or change body weight) and are comparing proportions between two different groups within the population. The options provided (population mean, population proportion, sample mean, sample proportion) help identify the nature of the statistic in question. Since we are concerned with the proportion of a characteristic within a population, the correct choice is population proportion, which is denoted as the true value of the proportion in the entire population (not just the sample).
Statistical analysis in this context might involve using a hypothesis test for two proportions, specifically testing the null hypothesis that the proportions of men and women wanting to stay at their current weight are equal against the alternative hypothesis that they are not equal.