Descriptive Statistics

• Mean: The average of all results
• Strength of mean: Reflects the values of all data in the final calculation
• Weakness of mean: Cannot be used with nominal data
• Weakness of mean: Unrepresentative if there are extreme values
• Median: Place all values in order from smallest to largest, and select the middle value
• Strength of Median: Not affected by extreme scores
• Weakness of Median: Not as sensitive as mean, as not all values are reflected
• Mode: Identify the most common group
• Strength of Mode: Useful when the data is in categories (nominal data)
• Weakness of mode: Ineffective when there are multiple modes
• Range: Arranging data in numerical order and subtracting the highest value from the lowest
• Strength of Range: Easy to calculate
• Weakness of range: Is unrepresentative, as it doesn't take distribution into account
• Weakness of range: Affected by extreme values
• Variance: Each number is subtracted from the mean, ignoring plus or minus values. The resultant differences are added up and a mean value is calculated
• Standard deviation: Square root of the variance
• Strength of SD/Variation: Measures dispersion precisely as all the exact values are accounted for
• Weakness of SD/Variation: May hide extreme values or other data characteristics