The median class in the following frequency distribution is
`{:("Class interval :",0-10,10-20,20-30,30-40,40-50),("Frequency :",12,13,25,20,10):}`

Options

A. `10-20`
B. `20-30`
C. `30-40`
D. none of these

Explanation

To find the median class from the given frequency distribution, we will follow these steps:

### Step 1: Write down the class intervals and their corresponding frequencies.
- Class intervals: 0-10, 10-20, 20-30, 30-40, 40-50
- Frequencies: 12, 13, 25, 20, 10

### Step 2: Calculate the cumulative frequency.
- Cumulative frequency for each class interval:
- For 0-10: 12
- For 10-20: 12 + 13 = 25
- For 20-30: 25 + 25 = 50
- For 30-40: 50 + 20 = 70
- For 40-50: 70 + 10 = 80

So, the cumulative frequencies are:
- 0-10: 12
- 10-20: 25
- 20-30: 50
- 30-40: 70
- 40-50: 80

### Step 3: Find the total frequency (N).
- Total frequency (N) = 80

### Step 4: Calculate N/2.
- N/2 = 80/2 = 40

### Step 5: Identify the median class.
- We need to find the cumulative frequency that is just greater than N/2 (which is 40).
- From the cumulative frequencies:
- 0-10: 12 (not greater than 40)
- 10-20: 25 (not greater than 40)
- 20-30: 50 (greater than 40)

The cumulative frequency of the class interval 20-30 is the first one that is greater than 40.

### Conclusion:
- Therefore, the median class is **20-30**.

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