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Pooling a sample variance is done to obtain a more accurate estimate of the population variance when combining data from multiple groups or samples. It is particularly useful when the samples have similar variances, as it allows for the incorporation of information from all samples, increasing the overall estimate's reliability. By weighting each sample's variance according to its size, pooling helps to reduce the impact of sampling error and provides a more robust basis for inferential statistics, such as hypothesis testing.

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Why the sample variance is an unbiased estimator of the population variance?

The sample variance is considered an unbiased estimator of the population variance because it corrects for the bias introduced by estimating the population variance from a sample. When calculating the sample variance, we use ( n-1 ) (where ( n ) is the sample size) instead of ( n ) in the denominator, which compensates for the degree of freedom lost when estimating the population mean from the sample. This adjustment ensures that the expected value of the sample variance equals the true population variance, making it an unbiased estimator.


What is the sample variance of 5781010 and 14?

The variance is: 1.6709957376e+13


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.


What is the sample variance with the mean of 190.3?

The mean, by itself, does not provide sufficient information to make any assessment of the sample variance.


What is the relation between a t-test value and the sample variance?

The t-test value is calculated using the sample mean, the population mean, and the sample standard deviation (which is derived from the sample variance). Specifically, the formula for the t-test statistic incorporates the sample variance in the denominator, adjusting for sample size through the standard error. A smaller sample variance typically results in a larger t-test value, indicating a greater difference between the sample mean and the population mean relative to the variability in the sample data. Thus, the relationship is that the t-test value reflects how the sample variance influences the significance of the observed differences.

Related Questions

What is the proof that the sample variance is an unbiased estimator?

The proof that the sample variance is an unbiased estimator involves showing that, on average, the sample variance accurately estimates the true variance of the population from which the sample was drawn. This is achieved by demonstrating that the expected value of the sample variance equals the population variance, making it an unbiased estimator.


Why the sample variance is an unbiased estimator of the population variance?

The sample variance is considered an unbiased estimator of the population variance because it corrects for the bias introduced by estimating the population variance from a sample. When calculating the sample variance, we use ( n-1 ) (where ( n ) is the sample size) instead of ( n ) in the denominator, which compensates for the degree of freedom lost when estimating the population mean from the sample. This adjustment ensures that the expected value of the sample variance equals the true population variance, making it an unbiased estimator.


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.


Is there a proof that demonstrates the unbiasedness of the sample variance?

Yes, there is a mathematical proof that demonstrates the unbiasedness of the sample variance. This proof shows that the expected value of the sample variance is equal to the population variance, making it an unbiased estimator.


Is sample variance unbiased estimator of population variance?

No, it is biased.


What is the sample variance of 5781010 and 14?

The variance is: 1.6709957376e+13


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.


Can the variance of a sample be negaTIve?

No.


What is the sample variance with the mean of 190.3?

The mean, by itself, does not provide sufficient information to make any assessment of the sample variance.


Do you have a sample school variance letter?

no


What does it mean to say that the sample variance provides an unbiased estimate of the population variance?

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.


If a sample of size 3 students showed the following grades in a certain exam 74 75 and 76 then the variance is?

The sample variance is 1.