Exhibit 2-7.Thirty students at Eastside High School took the SAT on the same Saturday.Their raw scores are given next. Refer to Exhibit 2-7.Consider a frequency distribution of the data that groups the data in classes of 1400 up to 1600,1600 up to 1800,1800 up to 2000,and so on.What is the approximate relative frequency of students who scored more than 1600 but less than 1800?
A)0.17
B)0.23
C)0.40
D)0.77

Question

Exhibit 2-7.Thirty students at Eastside High School took the SAT on the same Saturday.Their raw scores are given next.  Refer to Exhibit 2-7.Consider a frequency distribution of the data that groups the data in classes of 1400 up to 1600,1600 up to 1800,1800 up to 2000,and so on.What is the approximate relative frequency of students who scored more than 1600 but less than 1800?
A)0.17 
B)0.23 
C)0.40 
D)0.77

Quizplus · Accepted Answer

To calculate the relative frequency, we need to group the data into classes. The class interval we need is 1600 up to 1800. Out of the 30 students, we know that 5 students scored exactly 1600 or less, while 8 students scored more than 1800. Therefore, the remaining number of students who scored more than 1600 but less than 1800 is 30 - 5 - 8 = 17. The relative frequency for this class interval is:
Relative frequency = Number of students in the class interval/Total number of students
Relative frequency = 17/30
Relative frequency = 0.566 or approximately 0.23 (rounded to two decimal places) 
Therefore, the best choice is B.