# Tag Info

Accepted

### How to report the between study variance through tau2 for vaccine effectiveness using R's metafor?

You cannot transform the $\tau^2$ value that way. Also, most people will struggle to understand the estimate of $\tau^2$ (or some transformed version thereof if this was possible) in the first place. ...
• 17.6k

### Can population variance from multiple studies be averaged to use for a sample size calculation?

This may seem like a sinple question, but it is actually more involved than it first appears. Short answer; yes, that is an acceptable approach. But simple averaging may be a coarse approximation, as ...
• 3,282

### Can population variance from multiple studies be averaged to use for a sample size calculation?

You need to use formulae for the pooled variance of subgroups Obtaining a pooled variance from multiple subgroups is a bit more complicated than what you are proposing here (see related question here)....
• 130k
Accepted

• 9,577
Accepted

### Question About Approximating the Variance of the Sample Mean for an AR(1) Process

I think the book may be using different notation from your proof (it would be strange if it were wrong about a simple fact like this in a 5th edition) Write $\sigma^2_X$ for the marginal variance of \$...
• 43.3k