Underpowered

*[This blog draws on the article “*The statistical significance filter leads to overoptimistic expectations of replicability”, authored by Shravan Vasishth, Daniela Mertzen, Lena A. Jäger, and Andrew Gelman, published in the Journal of Memory and Language, 103, 151-175, 2018. An open access version of the article is available here.] The Problem Statistics textbooks tell us that the sample mean is an unbiased estimate of the true mean.