Exploring Higher Order Moments and Sample Size Infinity in Random Variables

In summary, the conversation discusses the relationship between a random variable's variance and higher order central moments as the sample size tends to infinity. The question is whether the higher order moments also tend to zero when the variance does. There is also a discussion about the difference between a random variable's distribution and its relationship to sample size.
  • #1
benjaminmar8
10
0
Hi, all,

Let's assume a random variable's variance is zero as sample size tends to infinity somehow, can I say that its higher order central moments are also zero as the sample size tends to infinity?

Thks a lot
 
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  • #2
That makes sense to me given that when the variance gets very small the higher order central moments should tend to zero faster then the variance because the square of a small quantity is even smaller then that small quantity.
 
  • #3
Your question really doesn't make sense: a random variable has a single distribution (normal distribution, chi-square distribution, etc) and does not depend on a sample size. if you respond "t-distribution" - that doesn't fit your comment: t-distributions are INDEXED by their degrees of freedom, but there is no requirement that there be a link to sample size.do you mean this:
if, in a series of samples of increasing sample size, if the sample variance tends to zero then all higher-order moments tend to zero?

or do you mean this:

if a (degenerate) distribution has variance zero, are all higher-order moments equal to zero.

One other possibility: are you talking about the behavior of SAMPLING distributions as the sample size tends to infinity?
 

Related to Exploring Higher Order Moments and Sample Size Infinity in Random Variables

1. What are higher order moments?

Higher order moments are statistical measures that describe the shape, variability, and distribution of a dataset. They are calculated by taking the nth power of the deviations from the mean, where n is the order of the moment. The first four moments (mean, variance, skewness, and kurtosis) are commonly used, but higher order moments provide more detailed information about the data.

2. How are higher order moments used in data analysis?

Higher order moments are used to gain a deeper understanding of a dataset. They can help identify outliers and asymmetry in the data, and they provide information about the tails of the distribution. They are also used in some statistical tests and models, such as the higher order partial correlation test and the higher order logistic regression model.

3. Can higher order moments be negative?

Yes, higher order moments can be negative. Moments are calculated by taking the deviations from the mean, so if there are data points that are far below the mean, the higher order moments will be negative. For example, a dataset with a high kurtosis value (fourth moment) may have a negative kurtosis, indicating a very peaked distribution with heavy tails.

4. How does the interpretation of higher order moments differ from lower order moments?

The first two moments (mean and variance) are used to describe the center and spread of the data, while the higher order moments provide information about the shape and distribution. For example, a dataset with a high skewness value (third moment) will have a long tail in one direction, while a dataset with a high kurtosis value (fourth moment) will have a more peaked distribution with heavier tails. Therefore, higher order moments provide a more detailed description of the data.

5. Are higher order moments affected by outliers?

Yes, higher order moments can be affected by outliers, especially in smaller datasets. Outliers can greatly impact the higher order moments, especially the kurtosis value, which is heavily influenced by extreme values. It is important to identify and handle outliers appropriately when interpreting higher order moments.

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