decision guide, Appendix F Q13 nonresponse bias, **Ch.4 section 4.3** normal distribution, **Ch.10 section 10.5** - `scipy.stats.norm`, Ch.10 section 10.7 - standard normal, **Ch.10 section 10.6** normality assumption, **Ch.15 section 15.6** `np.random.choice()`, Ch.11 section 11.3, Ch.18 section 18