Based on a study on midterm grades of 2000 students, a college professor found that the five-number summary is 10, 28, 55, 72, and 80, respectively. The total points for the exam are out of 100 points. The professor also found that the average midterm grade is 60 with a standard deviation of 10. Use the above information to answer 1a to 1d.
1a. Approximately how many students scored above 60? (1 pt)
A) Between 0 and 500 students
B) Between 500 and 1000 students
C) Between 1000 and 1500 students
D) Between 1500 and 2000 students
E) Exactly 1000.
1b. Which of the following ranges contains the most students? (1 pt)
A) 0 to 20
B) 20 to 28
C) 28 to 55
D) 55 to 70
E) 70 to 80
1c. Which of the following describes the shape of the distribution? (1 pt)
A) Skew to the right because the mean is greater than the median.
B) Skew to the right because the mean is less than the median.
C) Skew to the left because the mean is greater than the median.
D) Skew to the left because the mean is less than the median.
1d. Suppose Helen scored 25 points on the midterm. We can conclude that: (1 pt)
A) Her grade is the 3rd quartile of the group.
B) Exactly 25% of the students are doing better than Helen.
C) Her grade is the 1st quartile of the group.
D) Her grade is the 2nd quartile of the group.
E) None of the above.