What does a variance of 3.65 mean for my data?

Join the discussion
Registration is free. Start your own thread to ask a follow-up.
4 replies · 3K views
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 [tex]\mu - \sqrt{3.65}[/tex] and [tex]\mu + \sqrt{3.65}[/tex], if your mean is [tex]\mu[/tex].

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 [tex]\mu - \sqrt{3.65}[/tex] and [tex]\mu + \sqrt{3.65}[/tex], if your mean is [tex]\mu[/tex].

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.