A radio advertiser wishes to choose a sample of size 100 from a population of 5000 listeners. He divides the population into five separate groups and then selects a simple random sample from each group. This method of sampling is called

Please answer the question on the photo.

Race organizers want to survey the participating runners on the quality of the running course. Which of the following uses systematic random sampling? Select the first 15 finishers and the last 15 finishers to take the survey. Randomly select 15% of the male participants and 15% of the female participants. Select the 5th finisher (with the number 5 being randomly chosen) to survey, then survey every 15th finisher after that. Sort all of the runners' names alphabetically, then randomly choose 2 letters and survey all participants whose last name begins with one of those letters.

A coach is interested in how many slam dunks the average college freshman at his university can do. Ten volunteers from the senior class step forward. After observing their performance, the coach concluded that college seniors can do an average of 10 slam dunks in a row without missing. what is the sample? what is the population?