Question

In a grouped frequency table, if the class intervals are 5-15, 15-25, 25-35, and 35-45 with frequencies 12, 6, and 4 respectively, the median class interval is

• A. 5-15
• B. 15-25
• C. 25-35
• D. 35-45

Answer 1

Answer: (A)

5-15

Answer 2

To find the median class interval for a grouped frequency table:

1. Calculate Cumulative Frequencies: Determine the cumulative frequency for each class interval.

2. Find the Median Position: Calculate $N/2$, where $N$ is the total frequency.

3. Identify the Median Class: The median class is the class interval where the cumulative frequency is first greater than or equal to $N/2$.

Given frequencies: 12, 6, 4 (Total frequency $N = 22$)

Cumulative frequencies:

• 5-15: 12
• 15-25: 18
• 25-35: 22

$N/2 = 11$

The cumulative frequency for the class interval 5-15 is 12, which is the first value greater than or equal to 11. Therefore, the median class interval is 5-15.