Measures of Location (Central Tendency)

• Mean (Average) The sum of all data points divided by the number of data points.
  Formula: Mean = (Sum of all values) / (Number of values)
• Median The middle value in a data set that has been arranged in order from smallest to largest. If there is an even number of values, the median is the average of the two middle values.
• Mode The value that appears most frequently in a data set. A data set can have one mode (unimodal), two modes (bimodal), more than two modes (multimodal), or no mode.
• Relationship between Mean, Median, and Mode Symmetrical Distribution: Mean = Median = Mode.
  Positively (Right) Skewed: Mean > Median > Mode.
  Negatively (Left) Skewed: Mode > Median > Mean.

Measures of Dispersion (Variability)

• Range The difference between the highest and lowest values in a data set.
  Formula: Range = Maximum Value - Minimum Value
• Variance (s²) The average of the squared differences from the Mean. It measures how far a set of numbers is spread out from their average value.
  Formula (Ungrouped): s² = [Sum of (each value - mean)²] / (n - 1)
• Standard Deviation (s) The square root of the variance. It is the most common measure of spread and indicates the typical distance between a data point and the mean.
  Formula: s = sqrt(Variance)
• Coefficient of Variation (CV) A relative measure of dispersion that expresses the standard deviation as a percentage of the mean. It is useful for comparing the variability of two or more data sets with different units or means.
  Formula: CV = (Standard Deviation / Mean) * 100%