HW3 Grading Key (Biostat) Assigned 9/13; due 9/20; returned 9/27 [answers to 3.3, 3.5, 3.7, 3.9, and 3.15 are in their usual location]

Point value	Key &comments
	3.4 (A) mean at 3 (B) mean at 3 (C) No. The mean tells you nothing about variability.
	3.6 Values are equivalent. Groups have equal variability.
	3.8 95% are between 80 and 120
4 points only the means and standard deviations are graded	3.10 8 observations per group. Data are particulate air pollution  �g / m2 (A) = 36.25 (report as 36.3) and s = 14.6 (B) =  36.0 and s = 2.9 (C) Eight samples were taken from each site. The sites have similar averages levels of particulate pollution (36.3 vs. 36.0), but site 1 has much greater variability (standard deviations are 14.6 and 2.9, respectively).
6 points  5 points for 5 point summary 1 point upper outside value	3.16 Boxplot of the SEIZURE data - induction between meningitis and seizures (months), n = 13 5-point summary: 0.1, 4, 24, 36, 96 IQR = 36 - 4 = 32  FL  = 4 - (1.5)(32) = -44; there are no lower outside values; the lower inside value is 0.10. FU  = 36 + (1.5)(32) = 84; there is one upper outside value (96);  the upper inside value is 55. Here's the boxplot