Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams, May 2018 — 04-Env-B7, Environmental Sampling and Analysis (3 hours, closed book, approved non-programmable calculator only, statistical tables provided). The paper instructs "answer all 5 questions"; this solution answers all 5 in full.
Reference texts: Walpole, Myers, Myers & Ye, Probability & Statistics for Engineers and Scientists (sampling designs, hypothesis tests, EDA, ANOVA); Davis & Cornwell, Introduction to Environmental Engineering, ch. 2 (sampling protocol, QA/QC, monitoring program design).