1.An AP Statistics class starts a project to estimate the average number of hours a student at their high school sleeps per night. Their high school has 1200 students, and they take a sample of the first 120 students that arrive at school on a particular day. They ask each of the 120 students how many hours of sleep they got before and then calculate an average. Which of the following statements is an accurate description of the elements of this survey?

(a) Population: the 120 students surveyed. Parameter of Interest: the average number of hours a student at this high school sleeps per night.

(b) Sample: the 1200 students of the school. Population: all high school students in the United States. Statistic: the average nymber of hours a student at this high school sleeps per night.

(c) Sample: the 120 students surveyed. Population; the 1200 students at the high school. Parameter of Interest: the average number of hours a student at this high school sleeps per night.

(d) Sample: the 120 students surveyed. Population: the 1200 students at the high school. Statistic: the average number of hours a student at this high school sleeps per night.

(e) This is not a survey because a convenience sample was used.

2.At a high school, the cafeteria staff provides optional comment cards to students eating in the cafeteria. Students who wish to make a comment can obtain and fill out a comment card and return it to a drop box in the front office. At the end of the semester, the staff analyses the responses and finds that 72% of the students who filled out a comment card recommend major changes to the food selection. What conclusions can the cafeteria staff draw from these responses?

(a) Since all of the students had an opportunity to respond, this is evidence that a majority of all the students support major change.

(b) The cafeteria stand should not use the results to draw any conclusions since some of the students may not have filled out a comment card, which is nonresponse.

(c) If the students recorded their grade level with their response, the staff could make the original sample s stratified sample and use the responses to learn what proportion of each grade recommends a major changes to food selection.

(d) The responses were from a voluntary response sample, so the cafeteria staff should not use the results to draw any conclusions.

(e) The opportunity to fill out comment cards should be offered to students at all high schools in the school district to get a larger sample size, which will make the results more reliable.

3.The Career Placement department at a university wants to administer a survey to determine student awareness of the resources offered. The department expects the student awareness of the Career Placement resources will vary significantly depending on how many years as a student has attended the university, so they plan to randomly select 30 freshmen, 30 sophomore, 30 juniors, and 30 seniors. This type of sample can be best described as a

(a) simple random sample

(b) systematic sample

(c) stratified sample

(d) cluster sample

(e) block sample