Question

what is the median class?
2 points
the table shows the result of thirty students basic statistics test scores.

scores	students
30 – 39	1
40 – 49	10
50 – 59	11
60 – 69	5
70 – 79	2

options:

• 30-39
• 60-69
• 50-59
• 40-49

Explanation:

Step1: Calculate total number of students

The total number of students \( N \) is the sum of the number of students in each class. So, \( N = 1 + 1 + 10 + 11 + 5 + 2 = 30 \).

Step2: Find the median position

The median position is given by \( \frac{N}{2}=\frac{30}{2} = 15 \).

Step3: Calculate cumulative frequencies

• For the class \( 10 - 29 \), cumulative frequency \( cf = 1 \).
• For the class \( 30 - 39 \), \( cf = 1 + 1 = 2 \).
• For the class \( 40 - 49 \), \( cf = 2 + 10 = 12 \).
• For the class \( 50 - 59 \), \( cf = 12 + 11 = 23 \).

We need to find the class where the cumulative frequency is greater than or equal to the median position (15). The cumulative frequency for \( 40 - 49 \) is 12 (less than 15) and for \( 50 - 59 \) is 23 (greater than 15). So the median class is \( 50 - 59 \).

Answer:

C. 50-59