The measure of dispersion is used to describe the spread of data around a central value. In the context of a data set containing actual and projected sales, the measure of dispersion will help to understand the variability or consistency of sales figures. The variance is themost appropriate statistical method for finding the measure of dispersion because it calculates the average of the squared differences from the Mean, providing a clear picture of data spread. It is especially useful in comparing the spread between different data sets and understanding the distribution of data points.
* Mean is a measure of central tendency, not dispersion.
* Correlation measures the relationship between two variables, not the spread of a single variable.
* Confidence intervals are used to estimate the range within which a population parameter will fall, but they do not measure dispersion within the data set itself.
References:
* Measures of Dispersion in Statistics1
* Measures of Dispersion - Definition, Formulas, Examples2
* Statistical dispersion - Wikipedia3