Indicators of central tendency - mean, median and mode

2 Indicators of central tendency - mean, median and mode 

The term indicator of central tendency describes any statistic that is used to indicate an average value around which the data are clustered. Three possible indicators of central tendency are in common use - the mean, median and mode. 

The usual approach to showing the central tendency of a set of data is to quote the average. However, academics abhor such terms as their meanings are far too well known. We naturally prefer something a little more obscure - the mean . 

Our first example set of data concerns a series of batches of vaccine. Each batch is intended to be of equal potency, but some manufacturing variability is unavoidable. A series of 10 batches has been analysed and the results are shown in Table 2.1. 

The sum of all the potencies is 991.5 and dividing that by the number of observations (10) gives an average or mean activity of 99.15 units/ml. 

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