Why is median better than mean




















Moreover, it is the basis of many advanced statistical methods. For example, the mean is needed to calculate the standard deviation , which is the most prominent measure to assess the variability in a set of data. And it is also needed for many statistical testing procedures, e.

We assume that is a correct value, but that a device failure leads to the false measurement of The mean of the resulting five values now is instead of , as calculated from the original data, thus showing a considerable effect of the incorrect measurement. As before, the value is in the centre of the data row, so the median actually is unaltered by the false measurement.

An example for such a distribution in the context of an observational study is the time since the onset of a particular disease. In many cases, the date of diagnosis is close to the time of reporting, i. However, the study group often also includes patients who have been suffering from the disease for many years. If we calculate the mean of the individual time spans since disease onset, such large values have an enormous impact, making the mean larger than the actual distribution of data would suggest.

Therefore, here the median gives a more realistic picture of the data. If they are not too different , use the mean for discussion of the data, because almost everybody is familiar with it. If both measures are considerably different, this indicates that the data are skewed i. Stuck in the middle — mean vs.

As an example, let us consider the following five measurements of systolic blood pressure mmHg : , , , , Find out more or adjust your settings.

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Your information will be shared with these service providers where necessary to provide you with the service you have requested, whether that is accessing our website or ordering goods and services from us. We do not display the identities of our service providers publicly by name for security and competitive reasons. The reason that mean cannot be applied to all distributions is because it gets unduly impacted by values in the sample that are too small to too large.

The disadvantage of median is that it is difficult to handle theoretically. There is no easy mathematical formula to calculate the median. There are many ways to determine the central tendency , or average, of a set of values. The mean discussed above is technically the arithmetic mean, and is the most commonly used statistic for average.

There are other types of means:. The geometric mean is defined as the n th root of the product of n numbers, i. Geometric means are better than arithmetic means for describing proportional growth. For example, a good application for geometric mean is calculating the compounded annual growth rate CAGR. The harmonic mean is the reciprocal of the arithmetic mean of the reciprocals. The harmonic mean H of the positive real numbers x 1 , x 2 , A good application for harmonic means is when averaging multiples.

The arithmetic mean, geometric mean and harmonic mean together form a set of means called the Pythagorean means. For any set of numbers, the harmonic mean is always the smallest of all Pythagorean means, and the arithmetic mean is always the largest of the 3 means. Mean can be used as a figure of speech and holds a literary reference.

It is also used to imply poor or not being great. Median , in a geometric reference, is a straight line passing from a point in the triangle to the centre of the opposite side. Share this comparison:.

If you read this far, you should follow us:. Diffen LLC, n. MS Excel and others programs have the function to create median. Mean vs.



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