In a class of 200 students, Bill's mark corresponded to a z-score of 1 and Tom's mark corresponded to a z-score of 2.If the distribution of marks was bell-shaped ('normal') than the number of students with a
Grade between Bill's mark and Tom's mark is closest to
A)5
B)10
C)20
D) 30

Question

Quizplus · Accepted Answer

In a normal distribution, the difference between a z-score of 1 and 2 covers approximately 13.6% of the data. Therefore, for 200 students, 13.6% of 200 is closest to 27.2, which rounds to approximately 30 students.

In a Class of 200 Students, Bill's Mark Corresponded to a Z-Score