CENTRAL TENDENCY AND VARIABILITY(UNGROUPED)

• Measures of Central Tendency - a single, central value that summarizes a set of numerical data. It attempts to describe what is ‘typical’ in a set of data.
• Mean, median, and mode are called measures of central tendency.
• Mean – average; sum of the data divided by the number of data.
• Median – the middle number of the set of datawhen the data are arranged in ascending or descending order.
• Mode – the number that occurs most frequently in the data (𝒙̂)
• Unimodal – 1 mode
• Bimodal – 2 modes
• Trimodal – 3 modes
• Multimodal – 4 or more modes
• Measures of Variability - Measures of degree of spread of the values; measures of dispersion or variation
• Range - The difference betweeen the higest score (h.s.) and the lowest score (l.s.)
• Mean Deviation - Use of all scores in a distribution
• Variance and Standard Deviation - Use to immediately compare the spread of different sets of scores and enables to interpret the scores of the given data.
• Variance (𝒔 𝟐 ) - The quotient of the sum of the squared deviations from the mean divided by 𝑛 − 1
• Standard Deviation (𝒔) - the square root of the variance.