Question

Lawrence performs a survey to determine the average number of minutes of exercise seventh-grade athletes get in one week. He gets a list of sports and the seventh-grade students participating in each sport. He then chooses 10 people from each list to complete the survey. How can Lawrence’s sample be improved to be more representative of the population? 1. He can choose his sample from all seventh-grade students. 2. He can choose his sample from a list of students by class rather than by sport. 3. He can choose his sample from every third person on each list rather than 10 people. 4. He can choose his sample from a list of all athletes participating in each sport.

Answer 1

Answer:

1 is more representative.

Step-by-step explanation:

Answer 2

Answer:

1) Is more representative

Step-by-step explanation:

The problem with his selection is that maybe there are few students participating in certain sport and those students maybe do quite more excercise than the rest (or quite less). This will modify the results because the sample he selected is biased. This problem wont be solved by method 3 or 4, because he is still selecting students that may modify heavily the results with a high probability

This problem will also appear if he choose a sample by class. Maybe, in a class there are quite few students, and selecting from class will make those students appear quite more often than, lets say, a 7th grade student selected at random, therefore the selection is biased in this case as well.

If he has a list with all seventh grade students, each student is equallly likely to be selected and as a consequence, the the results wont be biased. Approach 1 is the best one.