What is the difference between mean and median?
The mean and median are two fundamental measures of central tendency used in statistics and data analysis. While both aim to describe the center of a data set, they do so in different ways and can yield different results depending on the distribution of the data.
The mean, commonly referred to as the average, is calculated by adding all the values in a dataset and dividing the sum by the total number of values. For example, in the dataset [2, 3, 5, 7, 10], the mean is (2+3+5+7+10)/5 = 5.4. The mean is sensitive to extreme values, or outliers, which can skew the result. If a very high or low number is introduced into the dataset (e.g., replacing 10 with 100), the mean will increase significantly, potentially misrepresenting the central tendency of the data.
The median, on the other hand, is the middle value of an ordered dataset. If the number of elements is odd, it’s the central value; if even, it’s the average of the two central values. In the dataset [2, 3, 5, 7, 10], the median is 5. Unlike the mean, the median is more robust to outliers. Using the same example with 100 instead of 10 ([2, 3, 5, 7, 100]), the median remains 5, reflecting the data’s central location more accurately.
In summary, the mean is ideal for symmetrical distributions without outliers, while the median is preferred for skewed distributions or when outliers are present. Understanding the distinction is crucial in data analysis, where choosing the right measure can lead to better insights and decisions.
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