Central range :
The central range in statistics is a measure of the spread of a set of data around its central value. It is calculated by taking the difference between the maximum and minimum values in a dataset and dividing by two. This measure provides important information about the dispersion of the data, which can be used to make inferences about the underlying population from which the sample was drawn.
For example, consider a sample of 100 observations on the height of adult males. The minimum height in the sample is 60 inches and the maximum height is 72 inches. The central range in this case would be (72 – 60) / 2 = 6 inches. This indicates that the majority of the observations in the sample are within 6 inches of the central value (i.e. the median height), with some observations falling outside of this range.
The central range is often used in combination with other measures of central tendency, such as the mean and median, to provide a more complete picture of the distribution of the data. For instance, if the mean height in the sample is 67 inches, this would suggest that the majority of observations are clustered around this value, with some observations falling above and below it. The central range of 6 inches would provide further information about the spread of the data, indicating that the majority of observations are within 6 inches of the mean.
The central range can also be used to compare the dispersion of two or more datasets. For example, consider a second sample of 100 observations on the height of adult females. The minimum height in this sample is 57 inches and the maximum height is 70 inches. The central range for this sample would be (70 – 57) / 2 = 6.5 inches. This indicates that the dispersion of the data in the second sample is slightly greater than in the first sample, with a wider range of heights observed.
One potential limitation of the central range as a measure of dispersion is that it only considers the minimum and maximum values in the dataset. This means that it can be influenced by extreme observations, which may not accurately reflect the overall distribution of the data. For instance, if a single outlier with a height of 100 inches were included in the sample of male heights, the central range would increase to (100 – 60) / 2 = 20 inches, even though the majority of the observations would still be clustered around the median value.
In practice, statisticians often use alternative measures of dispersion, such as the standard deviation or interquartile range, which are less sensitive to the influence of extreme observations. These measures provide a more accurate representation of the spread of the data, and are often preferred in statistical analysis.
Overall, the central range is a useful measure of dispersion that provides important information about the spread of a dataset.