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Jan 21, 2021 · Learn what pooled variance is and how to calculate it for two samples. Find out when to use the pooled variance formula and when to use Welch's t-test instead.
Definition and computation. The pooled variance is an estimate of the fixed common variance underlying various populations that have different means. We are given a set of sample variances , where the populations are indexed , = Assuming uniform sample sizes, , then the pooled variance can be computed by the arithmetic mean :
Learn how to estimate the common variance of two populations by pooling information from samples and how to use it to construct confidence intervals and hypothesis tests for the difference of two means. See the formula for the pooled variance and an example of comparing packing machines.
Jan 7, 2024 · The computational formula for the pooled variance is: s2 p = (n1 − 1)s2 1 + (n2 − 1)s2 2 n1 + n2 − 2. This formula can look daunting at first, but it is in fact just a weighted average. Even more conveniently, some simple algebra can be employed to greatly reduce the complexity of the calculation.
Mar 9, 2021 · Learn how to use the formula for pooled variance, which is the average of two or more group variances, in Excel. Follow a step-by-step example with data, formulas and screenshots.
Jan 17, 2023 · Learn what pooled variance is and how to calculate it for two samples. Find out when to use the pooled variance formula and when to use Welch's t-test instead.
Learn how to use the formula for pooled variance, which is a weighted mean of the group variances, given the group means, variances, and sample sizes. See the derivation, examples, and comments from experts and users on this Stack Exchange question.
