We have learnt that Lowest observation - highest observation = range. thats why range is correct answer

The correct answer is option 'C' - range.

The range of a given data refers to the difference between the maximum and minimum observations in the dataset. It is a simple measure of dispersion that provides information about how spread out the values are in the data.

To understand this concept better, let's break down the answer into the following sections:

1. Definition of Range:
- The range is the numerical measure that quantifies the spread or dispersion of a dataset.
- It is calculated as the difference between the highest and lowest values in the dataset.

2. Importance of Range:
- The range provides a quick and easy way to understand the variability or diversity of the data.
- It helps in identifying the spread of values and the extent to which the dataset deviates from the central tendency.
- Range is particularly useful when comparing two or more datasets.

3. Calculation of Range:
- To calculate the range, you need to find the maximum and minimum observations in the dataset.
- Subtract the minimum value from the maximum value to obtain the range.

4. Example:
- Let's consider a dataset of test scores: 65, 72, 80, 68, 90, 75, 82, 70.
- The maximum observation is 90, and the minimum observation is 65.
- Therefore, the range of this dataset would be 90 - 65 = 25.

5. Limitations of Range:
- While range provides a simple measure of dispersion, it only takes into account the extreme values.
- It ignores the values within the dataset, which can result in a misleading representation of the spread.
- Therefore, it is often useful to complement the range with other measures of dispersion, such as variance or standard deviation.

In conclusion, the range of a dataset is the difference between the maximum and minimum observations. It is a basic measure of dispersion that helps in understanding the spread of values in the data.