Question about what this variance value means

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Homework Help Overview

The discussion revolves around the interpretation of a calculated variance value of 3.65 from a set of measurements. Participants are exploring the implications of this variance in the context of statistical distributions, particularly normal distribution.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between variance and standard deviation, questioning how the variance value relates to the spread of data around the mean. There is a focus on the interpretation of the percentage of values within a certain range in a normal distribution.

Discussion Status

There is an ongoing exploration of the implications of the variance value, with some participants providing clarifications regarding the relationship between variance and standard deviation. Multiple interpretations of the statistical properties are being discussed, but no consensus has been reached.

Contextual Notes

Participants are operating under the assumption that the data follows a normal distribution, which is central to their interpretations of the variance value. There is also a mention of the distinction between population variance and sample variance.

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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?
 
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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.
 

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