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To calculate the confidence interval for variance or standard deviatio..
To calculate the confidence interval for variance or standard deviation, a statistical distribution called ______ is needed. => chi-square distribution or binomial distribution or poisson distribution or multinomial distribution..
Example:
Calculate the variance and standard deviation from the following data..
Calculate the variance and standard deviation from the following data.. Statistics - Calculating Variance. I give the formula and show one example of finding variance. For more free videos, visit JustMathTutoring.com
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Question : deviations by n-1?
Answer : So that the calculated sample variance S^2 is an UNBIASED estimator of sigma^2, the population variance. In other words to make E(S^2)=sigma^2. You might want to take a look at this http://en.wikipedia.org/wiki/Unbiased_estimator . The example shows exactly why we don't divide by just n... More from Yahoo Answers
Answer : So that the calculated sample variance S^2 is an UNBIASED estimator of sigma^2, the population variance. In other words to make E(S^2)=sigma^2. You might want to take a look at this http://en.wikipedia.org/wiki/Unbiased_estimator . The example shows exactly why we don't divide by just n... More from Yahoo Answers
Question : According to wiki:
The variance of a list of numbers expresses how large the differences between the list elements are. It can be defined in several ways such as the following algorithm: compute the difference between each possible pair of numbers; square the differences; compute the mean of these squares; divide this by 2. The resulting value is the variance.
Why do we need to divide it by 2?
What is the point of doing this?
Thank you very much. so why does wiki say we need to divide it..
Answer : Dividing with 2 --> because of "pair (2) of numbers"... More from Yahoo Answers
Answer : Dividing with 2 --> because of "pair (2) of numbers"... More from Yahoo Answers