Connection between mean and median

In summary, the conversation discusses the relationship between the mean and median of a dataset. It is mentioned that for a symmetric distribution, the mean and median will be the same, but for random numbers, this may not always be the case. The question is posed about the difference between the mean and median decreasing as the dataset size increases.
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dextercioby
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TL;DR Summary
See title and problem below.
I have 100 random real (even rational with only one decimal, like average temperatures of months at a particular weather station) numbers. With them I compute the arithmetical mean and the median. It is a (very) small probability they are the same number within let's say 0,1 or 0,2.

Question. If I let the number of items increase (let us say 1000 instead of 100), is it more probable that the difference between the mean and the median decreases? It is true that for a very, very large number of numbers this difference is arbitrarily close to 0, FAPP is 0?
 
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Mean and median will only be the same for a distribution symmetric around the mean. Example: (0,1,10) has a median of 1 and a mean of 11/3.
 
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I think that only applies to symmetric distributions, that the mean and median will approach the same value for very very large data sample.

mathman said:
Mean and median will only be the same for a distribution symmetric around the mean. Example: (0,1,10) has a median of 1 and a mean of 11/3.
The question was what will happen if you have very very large dataset. Your example has three numbers.
 
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malawi_glenn said:
I think that only applies to symmetric distributions, that the mean and median will approach the same value for very very large data sample.The question was what will happen if you have very very large dataset. Your example has three numbers.

No, they're suggesting a distribution that takes three values with equal probability
 

FAQ: Connection between mean and median

1. What is the difference between mean and median?

The mean is the average of a set of numbers, calculated by adding all the numbers and dividing by the total number of numbers. The median is the middle value in a set of numbers when they are arranged in order. If there is an even number of numbers, the median is the average of the two middle values.

2. How are mean and median related?

Mean and median are both measures of central tendency, or the middle value in a set of data. They are related in that they both give an idea of the "typical" or central value of a set of numbers. However, they can vary greatly depending on the distribution of the data.

3. When should I use mean instead of median?

Mean is often used when the data is normally distributed, or when there are no extreme values (outliers) in the dataset. It is a good measure of central tendency when the data is symmetrical. Median, on the other hand, is often used when the data is skewed or has outliers, as it is less affected by extreme values.

4. Can mean and median be the same?

Yes, in some cases, mean and median can be the same value. This typically occurs when the data is symmetrical and there are no outliers. For example, in a dataset with values 1, 2, 3, 4, 5, the mean and median would both be 3.

5. What does it mean if the mean is greater than the median?

If the mean is greater than the median, it can indicate that the data is positively skewed, meaning there are more values on the lower end of the scale. This can be caused by outliers or extreme values pulling the mean higher. It is important to consider the shape of the data when interpreting the relationship between mean and median.

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