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What does it mean to say that the sample variance provides an unbiased estimate of the population variance?
Wiki User
∙ 11y ago
It means you can take a measure of the variance of the sample and expect that result to be consistent for the entire population, and the sample is a valid representation for/of the population and does not influence that measure of the population.
Wiki User
∙ 11y ago
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Symbol for population variance?
the small greek letter sigma squared.
From a population with a variance of 900 a sample of 225 items is selected At 95 percent confidence the margin of error is?
3.92
What are the variances in a 4 variance analysis?
efficiency variance, spending variance, production volume variance, variable and fixed components
Which is not a measure of dispersion range or variance?
Variance
Can the Variance ever be smaller than standard deviation?
Yes. If the variance is less than 1, the standard deviation will be greater that the variance. For example, if the variance is 0.5, the standard deviation is sqrt(0.5) or 0.707.
Is sample variance unbiased estimator of population variance?
No, it is biased.
Standard deviation considered a crude measure of variance?
No. Well not exactly. The square of the standard deviation of a sample, when squared (s2) is an unbiased estimate of the variance of the population. I would not call it crude, but just an estimate. An estimate is an approximate value of the parameter of the population you would like to know (estimand) which in this case is the variance.
Show that in simple random sampling the sample variance is an unbiased estimator of population variance?
It is a biased estimator. S.R.S leads to a biased sample variance but i.i.d random sampling leads to a unbiased sample variance.
When the null hypothesis is true the ratio of the between groups population variance estimate to the within groups population variance estimate should be about?
1
How do you prove that the sample variance is equal to the population variance?
You cannot prove it because it is not true.The expected value of the sample variance is the population variance but that is not the same as the two measures being the same.
Why sampling needed?
Sampling is needed in order to determine the properties of a distribution or a population. Sampling allows the scientist to determine the variance in an estimate.
Will The finite population correction factor lead to a wider confidence interval?
No since it is used to reduce the variance of an estimate in the case that the population is finite and we use a simple random sample.
What is the variance of 6.6 8.5 4.6 1.7 2.4?
(Population) variance = 6.4664
When do we use the unbiased formula of variance?
Variance is a characteristic parameter of a probability distribution: it is not a statistic. In any particular situation (with a few strange exceptions) it has only one value and therefore cannot have any bias.
What does n-1 indicate in a calculation for variance?
The n-1 indicates that the calculation is being expanded from a sample of a population to the entire population. Bessel's correction(the use of n − 1 instead of n in the formula) is where n is the number of observations in a sample: it corrects the bias in the estimation of the population variance, and some (but not all) of the bias in the estimation of the population standard deviation. That is, when estimating the population variance and standard deviation from a sample when the population mean is unknown, the sample variance is a biased estimator of the population variance, and systematically underestimates it.
The sample variance is always smaller than the true value of the population variance is always larger than the true value of the population variance could be smaller equal to or?
yes, it can be smaller, equal or larger to the true value of the population varience.
When using the distribution of sample mean to estimate the population mean what is the benefit of using larger sample sizes?
The variance decreases with a larger sample so that the sample mean is likely to be closer to the population mean.
