Yoshi is conducting a study of females who are of retirement age within the United States. Yoshi is interested in how their eating and exercise habits change once they are no longer working. Yoshi wanted to try to draw a simple random sample of this population, but her mentor suggested that might be a difficult task. Why might Yoshi have trouble drawing a simple random sample of American females who are of retirement age? The population is stratified. There is no agreement on what constitutes retirement age. Older adults tend to resist research participation. The population is large