If the class intervals of a frequency distribution are `1-10, 11-20, 21-30, …., 61-70`, Then the upper limit of `21-30` is

Options

A. 21
B. 30
C. 30.5
D. 20.5

Answer

To find the upper limit of the class interval `21-30` in a frequency distribution, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Class Intervals**: The given class intervals are `1-10`, `11-20`, `21-30`, ..., `61-70`.

2. **Determine the Upper Limit of the Interval**: The upper limit of the class interval `21-30` is the highest value in that interval, which is `30`.

3. **Adjust for Continuous Class Intervals**: In statistics, when dealing with continuous data, we often adjust the class intervals to avoid gaps. This is done by subtracting 0.5 from the lower limit and adding 0.5 to the upper limit of each class interval.
- For the interval `21-30`:
- Lower limit: `21 - 0.5 = 20.5`
- Upper limit: `30 + 0.5 = 30.5`

4. **Conclusion**: Therefore, the upper limit of the class interval `21-30` in a continuous frequency distribution is `30.5`.

### Final Answer:
The upper limit of the class interval `21-30` is **30.5**.

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