Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On regression adjustments in experiments with several treatments   Regression adjustments are often made to experimental data. Since
randomization does not justify the models, bias is likely; nor are the usual
variance calculations to be trusted. Here, we evaluate regression adjustments
using Neyman's nonparametric model. Previous results are generalized, and more
intuitive proofs are given. A bias term is isolated, and conditions are given
for unbiased estimation in finite samples.

26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys