You've all seen these before. These are the "eight schools" that everyone gets when being introduced to Bayesian programming. Here are the full data for your consideration, which you can use instead of awkwardly searching where the data are and copy-pasting them as a list. Every damn time, Steve.
A data frame with 8 observations on the following 6 variables.
a letter denoting the school
the number of students in the school receiving the treatment
the number of students in the school in the control group
the estimated treatment effect
the standard error of the effect estimate
the residual variance
Data copy-pasted from Table 1 in Rubin (1981).
Rubin, Donald B. 1981. "Estimation in Parallel Randomized Experiments." Journal of Educational Statistics 6(4): 377-401.