Situation 2 For questions 6 through 8 Alice teaches statist

Situation #2 – For questions 6 through 8

Alice teaches statistics to a large class of 150 students. Because Alice is extremely busy, she has decided to take a sample of 10 papers from one of the writing assignments and grade this sample instead of grading the entire 150 papers.

She decides that if the 10 papers she looks at from the sample are acceptable, then she will give everyone a perfect score. That is 30 points out of 30 points.

Likewise, since this is a statistics class and the sample is truly representative of the entire class, if the samples are not acceptable when she grades them, then she will give everyone the average score from those 10 papers. She figures that if anyone complains about the low score that she can justify the individual scores very easily because this is a writing assignment and she is sure she can find errors in ANY paper if she looks hard enough.

Question 6: If the papers are not acceptable from the sample and she gives everyone the average score that has been computed, what type of error is this when we know that most of the papers are acceptable? (1 point)

Question 7: If the papers are all acceptable from the sample and she gives everyone a perfect score when we know that not all papers can be perfect, what type of error is this? (1 point)

Question 8: As a student, do you agree or disagree with how the assignment grading will be handled? Why do you agree or disagree? Are there any statistical concepts to back your answer? (2 point)

Solution

Q6) Type I error, Reject null hypothesis when it is true

Q7) Type II error, Fail to Reject null hypothesis when it is False

Q8) Disagree with the sampling procedure, since the score are dependent on individual student performance.