Question

Q.1 Dr. Frank needs to choose 3 students from her Advanced Biology course to attend a conference in Hawaii. The course has 40 students. Which of the following methods could Dr. Frank use to choose a simple, random sample of 3 students? Select all that apply.

1 Dr. Frank could have the students line up from shortest to tallest, then use her birthdate, 2/5/39, to select 3 students from the line (the 2nd student, the 5th student, and the 39th student).

2. Dr. Frank could upload her class roster into a spreadsheet and use a ranom-number generating function to produce 3 random numbers. The students whose names are located in the rows with these 3 numbers on the spreadsheet would be chosen.

3. Dr. Frank could choose the students with the 3 highest grades in the class.

4. Dr. Frank could count to three, then the first students to come to the front of the classroom and grab a golden ticket from her hand would be selected.

5. Dr. Frank could ask all students to write their name on a card, place all of the cards in a hat, shake the hat, and then pull 3 cards out from the hat. The students whose names appear on those 3 cards will be selected.

6. Dr. Frank could ask for volunteers to go to the conference, then choose the first 3 students who raise their hands.

Q2. Now, choose ONE of the methods that you DID NOT select and explain why this method would NOT result in a simple, random sample:

Answer 1

Q1:

The methods that Dr. Frank could use to choose a simple, random sample of 3 students are: 2 and 5.

2. Dr. Frank could upload her class roster into a spreadsheet and use a ranom-number generating function to produce 3 random numbers. The students whose names are located in the rows with these 3 numbers on the spreadsheet would be chosen.

5. Dr. Frank could ask all students to write their name on a card, place all of the cards in a hat, shake the hat, and then pull 3 cards out from the hat. The students whose names appear on those 3 cards will be selected.

Q2:

6. Dr. Frank could ask for volunteers to go to the conference, then choose the first 3 students who raise their hands.

This is not a simple, random sample because the probability of choosing every student is not equal. This type of sample is called as 'Voluntary response sample'.