Evaluation of Descriptive Statistics
Psychology: AQA A Level, topic 7.3.4
Evaluation of Mean, Median, Mode & Measures of Dispersion
Here are the advantages and disadvantages of measures of dispersion and other measures.
Evaluation of the mean
- Advantages:
- The mean takes account of all values to calculate the average.
- Disadvantages:
- Very small or very large values can affect the mean (outliers or anomalies).
Evaluation of the median
- Advantages:
- The median is not affected by very large or very small values (outliers or anomalies)
- Disadvantages:
- If there is an even number of numbers, the median is found by averaging the two middle numbers. This means the median value may not actually exist as a score in the data.
Evaluation of the mode
- Advantages:
- The mode is the only measure of central tendency that can be used if the data set is nominal (categories), for instance the number of cat and dog owners in your class.
- Disadvantages:
- There can be more than one mode, and all values can be modal which means the mode is not always representative of the data.
Evaluation of standard deviation
- Advantages:
- Shows whether or not data is clustered around the mean.
- Not affected by extreme values or outliers.
- Disadvantages:
- Difficult to calculate.
- Does not show full range of data.
Evaluation of the interquartile range
- Advantages:
- Good for ordinal data.
- Not as affected by extreme values as the range.
- Disadvantages:
- Can be difficult to calculate.
- Does not use all of the data e.g. 25th-75th percentile only.
Evaluation of the range
- Advantages:
- Easy to calculate.
- Disadvantages:
- Affected by extreme values.