Question about what this variance value means

Click For Summary
SUMMARY

The variance value of 3.65 indicates the degree of dispersion of a dataset around its mean. In a normal distribution, approximately 69% of the data points fall within +/- 1.91 units (the square root of 3.65) of the mean. Variance is defined as the average of the squared distances between each data point and the mean, serving as a measure of data spread similar to standard deviation. The discussion clarifies that the population variance is the square of the population standard deviation.

PREREQUISITES
  • Understanding of statistical concepts such as variance and standard deviation
  • Familiarity with normal distribution properties
  • Basic knowledge of mathematical operations involving square roots
  • Ability to interpret statistical measures in data analysis
NEXT STEPS
  • Study the properties of normal distribution in depth
  • Learn about calculating and interpreting standard deviation
  • Explore the relationship between variance and standard deviation in statistical analysis
  • Investigate the implications of variance in real-world data sets
USEFUL FOR

Statisticians, data analysts, students studying statistics, and anyone interested in understanding data dispersion and its implications in analysis.

yopy
Messages
43
Reaction score
0
i calculated the variance of a few measurements and i got the value of 3.65

i know the variance tells us the degree of dispersion from them ean value, and i came up with 3.65, what does this number say about the data?
 
Physics news on Phys.org
If you're dealing with a normal distribution, it tells you that about 69% of your values are within +/- 3.65 units of the mean.
 
Mark44 said:
If you're dealing with a normal distribution, it tells you that about 69% of your values are within +/- 3.65 units of the mean.

thank you
 
Mark44 said:
If you're dealing with a normal distribution, it tells you that about 69% of your values are within +/- 3.65 units of the mean.

I thought that in a normal distribution, 69% of your values are within +/- one standard deviation of the mean. So in this case, 68-69% of the data will be in the interval between \mu - \sqrt{3.65} and \mu + \sqrt{3.65}, if your mean is \mu.

Variance is the average of the squares of the distance between your data and the mean. Like standard deviation, it also measures how spread out your data is.
 
mathie.girl said:
I thought that in a normal distribution, 69% of your values are within +/- one standard deviation of the mean. So in this case, 68-69% of the data will be in the interval between \mu - \sqrt{3.65} and \mu + \sqrt{3.65}, if your mean is \mu.

Variance is the average of the squares of the distance between your data and the mean. Like standard deviation, it also measures how spread out your data is.
Thanks for the correction. The (population) variance is the square of the (population) standard deviation.
 

Similar threads

  • · Replies 42 ·
2
Replies
42
Views
5K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 53 ·
2
Replies
53
Views
9K
  • · Replies 16 ·
Replies
16
Views
18K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 5 ·
Replies
5
Views
5K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K