Excluding mean in variance calculation

Click For Summary
SUMMARY

The discussion centers on the unconventional method of calculating variance by excluding the mean, as proposed in a finance book. The author suggests using the formula \(\frac{1}{N}\sum_{i=1}^n (x_i)^2\) to compute sample variance, which diverges from the traditional approach that incorporates the mean. Participants express skepticism about the validity and applicability of this method in financial contexts, emphasizing the importance of considering the mean for accurate variance calculations.

PREREQUISITES
  • Understanding of statistical concepts, specifically variance and mean.
  • Familiarity with financial time series analysis.
  • Knowledge of sample variance calculation methods.
  • Basic proficiency in mathematical notation and formulas.
NEXT STEPS
  • Research traditional variance calculation methods, including the role of the mean.
  • Explore the implications of excluding the mean in statistical analysis.
  • Study financial time series modeling techniques.
  • Learn about the second moment in statistics and its applications in finance.
USEFUL FOR

Finance professionals, statisticians, and data analysts interested in variance calculations and their implications in financial analysis.

Polymath89
Messages
27
Reaction score
0
I'm reading a finance book in which the author proposes to exclude the mean when calculating the variance of returns, because he thinks it's difficult to distinguish the drift of the price from the variance of that time series. So he basically calculates the sample variance like this \frac{1}{N}\sum_{i=1}^n (x_i)^2. I haven't seen anybody calculate variance like this before, so my question is whether this is a common way to calculate it or whether this could yield problematic results?
 
Physics news on Phys.org
This is the second moment. I doubt that it has a useful application in finance without looking at the mean of the values, but I don't know.
 

Similar threads

  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 7 ·
Replies
7
Views
6K
  • · Replies 28 ·
Replies
28
Views
3K
Replies
5
Views
6K
Replies
1
Views
4K
Replies
0
Views
1K
  • · Replies 8 ·
Replies
8
Views
12K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K