# s08_1 - Statistics 224/324 - lecture 1 (Bates) Midterm 1...

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Unformatted text preview: Statistics 224/324 - lecture 1 (Bates) Midterm 1 2008-02-28 (p. 1) In Homework 1 you examined the hellung data providing average cell diameters ( μ m) versus concentration for cell samples grown with and without glucose. Questions 15 to 21 relate to this output. > str(hellung) 'data.frame': 51 obs. of 3 variables: \$ glucose : Factor w/ 2 levels "Y","N": 1 1 1 1 1 1 1 1 1 1 ... \$ conc : int 631000 592000 563000 475000 461000 416000 385000 321000 302000 199000 ... \$ diameter: num 21.2 21.5 21.3 21 21.5 21.3 20.3 22.7 21.5 22.2 ... > summary(hellung) glucose conc diameter Y:32 Min. : 11000 Min. :19.20 N:19 1st Qu.: 27500 1st Qu.:21.40 Median : 69000 Median :23.30 Mean :164325 Mean :23.00 3rd Qu.:243000 3rd Qu.:24.35 Max. :631000 Max. :26.30 Cell diameter ( μ m) Y N 20 22 24 26 ● ● Cell diameter ( μ m) Density 0.00 0.05 0.10 0.15 0.20 18 20 22 24 26 28 Y N Standard normal quantiles Cell diameter ( μ m) 20 22 24 26-2-1 1 2 ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●●● ● ● ● ● ● ●● ● ● ● ● ● ● ● Y N ● In Homework 3 you answered questions on the grain size in an aluminum-indium alloy for which the distribution is assumed to be normal with mean μ = 96 μ m and standard deviation σ = 14 μ m. Questions 22 to 25 relate to this output. > pnorm(c(80, 110), mean = 96, sd = 14) [1] 0.1265490 0.8413447 > diff(pnorm(c(80, 110), mean = 96, sd = 14)) [1] 0.7147958 > diff(dnorm(c(80, 110), mean = 96, sd = 14)) [1] 0.002452940 > qnorm(c(0.025, 0.975), mean = 96, sd = 14) [1] 68.5605 123.4395 Statistics 224/324 - lecture 1 (Bates) Midterm 1 2008-02-28 (p. 2) Multiple choice questions. Choose the most appropriate answer. Mark only oneMultiple choice questions....
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## This note was uploaded on 03/06/2010 for the course STATS 324 taught by Professor Bates during the Fall '08 term at University of Wisconsin.

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s08_1 - Statistics 224/324 - lecture 1 (Bates) Midterm 1...

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