 asked in category: General Last Updated: 20th June, 2020

# How do you know if variances are equal?

If the variances are equal, the ratio of the variances will equal 1. For example, if you had two data sets with a sample 1 (variance of 10) and a sample 2 (variance of 10), the ratio would be 10/10 = 1. You always test that the population variances are equal when running an F Test.

In this regard, what does it mean when variances are equal?

'variances equal' simply means that the population variance for one thing is the same as the population variance for some other thing or things.

Also, what is T test used for? A t-test is a type of inferential statistic used to determine if there is a significant difference between the means of two groups, which may be related in certain features. A t-test is used as a hypothesis testing tool, which allows testing of an assumption applicable to a population.

Regarding this, when can we assume equal population variances?

Two sample standard deviations are very similar so we will assume equal population variances. 95% confidence interval contains 0 so cannot rule out that the population means may be equal. If sample sizes are equal, the pooled and unpooled standard errors are equal.

What is a paired t test?

The paired sample t-test, sometimes called the dependent sample t-test, is a statistical procedure used to determine whether the mean difference between two sets of observations is zero. In a paired sample t-test, each subject or entity is measured twice, resulting in pairs of observations.

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20th June, 2020

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