30 July 2012

Median is more reliable than Mean (or Average) in Statistics Description???

Mean is an average of data. That is, the sum of data divided by the total number of data. Median, on the other hand, is simply the mid point of data. In this post, I quote an interesting and useful insight from a scientific journal paper about how can someone manipulates descriptive statistic by using Mean or Average value to depict data as follows:

“...Regular hourly employees, however, seldom earn more than $50,000 annually. Because the top management salaries are so high, the mean is strongly distorted by the very few extremely high salaries. Thus, the mean salary is much higher than a typical factory worker could ever earn. For example, if 1,000 employees earn $40,000 each, two top executives each earn $10 million, and the chief executive earns $20 million, the median salary is $40,000, but the mean salary is $79,670
almost $80,000 per year, and double what the average worker earns.

Politically, this plays out as follows:
Management knows that public opinion would not support a raise for factory workers in a company where the mean salary is $80,000. Thus, they publicize information that emphasizes that the mean salary is already $80,000 a year in their factory, and ask why a company paying such a high mean salary should award any raises especially in a tight economy...”
 (Source: McHugh, M. L., & Hudson-Barr, D. (2003). Descriptive Statistics, Part II: Most Commonly Used Descriptive Statistics. Journal for Specialists in Pediatric Nursing, 8, 111-116.)

So, can you see the trick?

I hope all my visitors will not be tricked by Mean.
Shared by: Xaivier Chia


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