(a) Of the school’s 1,000 students, about 200 are in each grade (Grades 8-12). Helen decides to use a random number generator to randomly pick 20 students from each grade. Explain why this type of random sample is not an SRS. (b) Helen remembers that there is a school play happening at the school that evening, and hundreds of students will be there. She decides to go to this gathering and randomly choose 100 of these students to survey. Explain why this type of sample may be biased, and how this may affect her results. (c) Helen decides that she will use an SRS to pick the 100 students. She takes an SRS of size 100 from the student list. However, upon closer inspection of this sample, she notices that very few of them are in Grade 12. Wanting to be fair to Grade 12 students, she decides to take a new SRS of size 100. This time, there is a fairly equal number of students in each grade, and she is satisfied. Explain why this is not a true SRS.
Helen is a member of her high school’s student council. She would like to survey students on whether they would like to hold a movie night at the end of the year. She decides to survey 100 of the university’s 1,000 students. Consider each of the following scenarios:
PLEASE ANSWER ASAP:
(a) Of the school’s 1,000 students, about 200 are in each grade (Grades 8-12). Helen decides to use a random number generator to randomly pick 20 students from each grade. Explain why this type of random sample is not an SRS.
(b) Helen remembers that there is a school play happening at the school that evening, and hundreds of students will be there. She decides to go to this gathering and randomly choose 100 of these students to survey. Explain why this type of sample may be biased, and how this may affect her results.
(c) Helen decides that she will use an SRS to pick the 100 students. She takes an SRS of size 100 from the student list. However, upon closer inspection of this sample, she notices that very few of them are in Grade 12. Wanting to be fair to Grade 12 students, she decides to take a new SRS of size 100. This time, there is a fairly equal number of students in each grade, and she is satisfied. Explain why this is not a true SRS.
(d) Suppose Helen takes an SRS of 100 students. She surveys them to see whether or not they would like to hold a movie night. However, she usually approaches people in the hallways, in front of their friends. She notices that, when she talks to people one-on-one after the survey, they are not actually as eager to attend the movie night as they appeared before. Explain why approaching people in front of their friends may result in a biased sample, and how this may affect Helen’s results.
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