Understanding the Mean: Exploring its Definition and Significance

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In summary, the conversation discusses the concept of mean and its definition as well as its practical application in different scenarios. The mean is defined as the weighted average of all possible values, taking into account their respective probabilities. However, in some cases, such as with a dice with colored sides, the mean may not have a clear interpretation due to the nature of the data. The conversation also brings up the distinction between the theoretical mean and the observed or sample mean.
  • #1
WiFO215
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I know what the definition of a mean is, but I'd like to know what it actually means. Let me give you an example. Suppose I have a regular dice, then the mean that I calculate using the normal process seems to say 3.5, although the dice will never realize that value. So what does it explain here?

What would the mean be if I had a dice with any 6 colors from VIBGYOR? In such a case, the mean isn't even defined properly is it? If I assigned each of the colors a number from 1-6, then I'd get a mean of 3.5 again which makes absolutely no sense. Odd to say that the mean in this case is turquoise. So what does it mean in this case?
 
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  • #2
anirudh215 said:
I know what the definition of a mean is, but I'd like to know what it actually means. Let me give you an example. Suppose I have a regular dice, then the mean that I calculate using the normal process seems to say 3.5, although the dice will never realize that value. So what does it explain here?

One interpretation: as the number of rolls becomes large, the expected total approaches the number of rolls times the mean.

anirudh215 said:
What would the mean be if I had a dice with any 6 colors from VIBGYOR? In such a case, the mean isn't even defined properly is it? If I assigned each of the colors a number from 1-6, then I'd get a mean of 3.5 again which makes absolutely no sense. Odd to say that the mean in this case is turquoise. So what does it mean in this case?

Colors aren't cardinal, so you can't give a mean. They also aren't ordinal, so you can't give a median. But you can give a mode, unhelpful as it may be in this case.

That's a natural hierarchy to me: as you go to less and less ordered sets, you can use fewer and fewer methods.
 
  • #3
anirudh215 said:
I know what the definition of a mean is...

To be absolutely clear, what definition are you using?
 
  • #4
Good grief. I hardly even remember starting this topic. I don't even know why I started it. I posted it just before going to sleep. But let's continue anyway. I've never heard the terms ordinal and cardinal, so I might learn something new.

@bpet : I am using the definition [tex] \overline{x} [/tex] = [tex]\sum x_{i}p(x)[/tex] where the xi are the realizations of a random variable X.
 
  • #5
So the "mean" is the weighted average of the possible values, weighted by their probability.

If you are talking about a discrete problem (as you are since you use sum, not integral), you can think of each possible outcome as having "multiplicity" according to its probability. In that case, the mean is just the arithmetic average of all possible outcomes.
 
  • #6
anirudh215 said:
I don't even know why I started it...
I am using the definition [tex] \overline{x} [/tex] = [tex]\sum x_{i}p(x)[/tex] where the xi are the realizations of a random variable X.

Ha, no it was a good question. You're on the right track - a random variable is an abstract object that maps an event space to real numbers and needn't have any physical meaning. For your coloured dice example the events (colours) could all be assigned to zero and the mean would be zero. Take care not to confuse the observed mean (sample mean) with the theoretical mean (expected value). Good luck with your studies!
 
  • #7
bpet said:
For your coloured dice example the events (colours) could all be assigned to zero and the mean would be zero. Take care not to confuse the observed mean (sample mean) with the theoretical mean (expected value).

1. How/ why can you map all the colors to zero?
2. What is observed mean and sample mean? The only mean I know of is the one I posted above and it's analog for the continuous case.
 

FAQ: Understanding the Mean: Exploring its Definition and Significance

What is the definition of 'mean'?

The term 'mean' can have multiple definitions depending on the context in which it is used. Generally, it can refer to the average or central value of a set of numbers, the intent behind a statement or action, or to describe someone who is unkind or malicious.

How is the 'mean' calculated in mathematics?

In mathematics, the 'mean' is calculated by adding up all the numbers in a set and then dividing the sum by the total number of values in the set. This is also known as finding the average. For example, if a set of numbers is 1, 3, 5, and 7, the mean would be (1+3+5+7)/4 = 4.

What does the 'mean' represent in statistics?

In statistics, the 'mean' is a measure of central tendency that represents the average value of a dataset. It is often used to summarize a large set of data and give a general idea of where the data falls on a number line. It can also be influenced by extreme values, known as outliers.

Can the 'mean' be the same as the 'median'?

Yes, the 'mean' and 'median' can be the same value. The median is the middle number in a dataset, while the mean is the average. If a dataset has an even number of values, the median is calculated by finding the average of the two middle values. In this case, the mean and median would be the same value.

How is the 'mean' used in everyday life?

The concept of 'mean' is used in various ways in everyday life. For example, when calculating your grade point average (GPA) in school, the 'mean' is used to represent your average grades. In sports, the 'mean' can be used to represent a player's average performance. It is also commonly used in finance to calculate the average return on investments or the average income of a population.

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