Exam 1 Key - Exam 1 for Math 1680 Name Date Zffifii/fig...

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Unformatted text preview: Exam 1 for Math 1680 Name: Date; Zffifii/fig Directions: Answer as many of the following questions as yea can. Box your final answer! If I can’t find your answer, I won’t grade it. Partial credit may be given for work shown, but a wrong answer without supporting work or justifications will receive no credit. A complimentary normal table has been provided at the back of your test. Feel free to tear it off and use it. Good Luck! '1; W Total Score: t @ /150 Question 1 (35 points): 3. (Hypothetical) An engineer knows from prior records that the distribution of weight on an elevator in an apartment building for each lift last year is approximately normal, with an average weight of 1000 lbs and a standard deviation of 150 lbs. :1) (10 points): What percentage of the time did the elevator lift more than 1100 lbs? _ [loo—WOO J z I, a %“ are q 3 "‘éé UKS'VXZ [claret "l: 4“) b’ d Lwl‘xj “I” E A: . (5— M “Hr +4-th jive} 6? Central We: of 7‘6 ,éé Llama _ To Jm m. {amt “lg/N imazwwfwz m” 01,-, a a, 2 (am {We/y) 15an izsim’ q, l b) (10 points): What percentage of the time did the elevator lift between 750 and 1100 mg? ‘ . Fm,“ 4)) we 1mm.) Has Met: inth 2:”:{! «J 23,55 3'; Ull:fi“y hm? higher “line 41:; £0” %50 h zit361;; “2‘5" 13 5,170 « A_ 754040” I; a, Mode, 71; We: 1424,56, If" 3 ‘ L09“? Jar Lg; 0.4 the Till/p jive/f f [$15,551 {195: of {70) “A”; M? We: .0 Z t“) 1%! L“; £91», “£55 to 0} khaki] , fifla‘li‘e «(134 we Min“! 1,; VZQJH’IZ‘l‘ Ltbioffdz, :— '70 c) (15 points): If the elevator’s maximum load capacity was 1200 lbs, what percentage of the time did the elevator’s load exceed its maximum capacity? exfwyr‘gj {gifliflflga mam} gaudy {(14913 “521691 32f)? “U 3” “a? a 55" at“ VH9 f . flea.er w W‘ {A the 5.54?” _ {W WMMW mp gag???) E » i!” 3’" "do m ’ Question 2 (20 points): (AP) An increasing number of city shooting victims have had previous brushes with the law, according to a new study by city criminologists. The report from researchers with the Philadelphia Adult Probation and i’arole Department found that 24 percent of shooting victims in 2006 had pending criminal court cases against them at the time they were shot. In 2002, the figure was 18 percent. Thirty percent of gun-homicide victims last year had pending criminal cases at the time they were killed, up from 20 percent in 2003, according to the report. The analysts did not attempt to categorize the pending charges against the victims to determine whether they were minor offenses or violent acts. However, researchers found that gun violence is larger confined to the city's poorest areas. a) (19 points) Was this study a controlied experiment or an observational study? Justify your answer! iii“ ‘5 X ft 1)) (5 points) identify the control and treatment groups. MT. i , , _ 4- , .r .". IE, fig/E ihc Vfo’mfit’u-x JP filaa‘ll'iy ‘ (fififwmiif Ibraifmj . Hqu ZOflé (%}pgt§;h€awi) i0 ff'a‘iliofiliis affix? 1mg but!) 51);} wiry Vlnfirfl-‘M “255;? {may . ‘P t I, (in ‘ "a lugs 4/ Jr."""“j: c) (5 points) Give at least one possibte confounding factor in this study, and explain Why it would be a confounding factor. ' fl ' u 9.! -' s .9. r n") M ' = I - t “ r H K1 "as tram eat-«raw t“. it it Even {kiwi m The Nitric That ‘i‘ixt mafia“, 5/39!” aria 'r" ‘ N f “a” m? ‘2 \ r Panda’s; they}; item/h “it”; titan»: “he? 57/me “ii 4 for.er “mm-5" OH?” 6 y] t“ "g 3 I}- my: H ilitt’h ' fiat (7 Italian fits/{'55s 5'7 mil?!“ (“MU / w . til/i455? U mm ‘ “Hm I .f’ i w , - a f I r P p r’ “r a 5’ x 71}; tittfcit wajfvti’ir/r {trait o‘igifiiit Issues? In. 3W i. J 0/1/51“; (’rrhr‘ Matty. Question 3 (35 points): The foflowing table shows the distribution of families by income in the US in 1973: $0 - $5,000 25 — '50 lit—:57 531 =95} 1,6 lbw) all 111%?!) Netting“: “HAQ flit? Lug?) haw {Le I‘M“: My“ - 79 ft? i; '3 fleas: a b) (10 points) Were there liker more famiiies with incomes of $12,000 - $13,000 or $20,000 — $21 000‘? E gm: gym MN 52%, [Jerfiiflm in ZNX} flfiéflwfij 2,6Z/Prqupw [A 711,? i190)” 1 J ‘ m ‘ ‘ w 1 if! ' a; “(if ,a . r a J a gw‘ F1 )2)! '15 LOX Continua; $3,010» “filler”, GVHKQ Th; @ficg A“: Milw- fim : ) Ne m J3”, f (bard? “file Aeifh‘fié'> c) (10 points) If a government officiak wanted to portray Americans as having high incomes, should he use the average or the median as a central tendency measure? E wk 71]“ (Mam: file om’waflfiiaa/afam "til .0 j - an? M“ £39 Light {garage/52:“ garage MP 45% $213?" (QFKAH flog Wm; Q I; Wow/(@JHKN 11:2 fie Gd”? mum; ‘an m: (M if) Question 4 (30 points): In a college statistics class, the comparison of height and weight for students results in the following summary. Average weight: 160 pounds SD for weight: 25 pounds Average height: 69 inches SD for height: 4 inches Correlation (r): 0.65 a) (10 points) Predict and give the RMS error for the height of a student weighing mum pounds' » {7 w e Wear“! 0’ 3 0% give"; Wzigg, {Zg*5Hi - “v . g Wflivrw W gs” *to i A guy“ mvEEfW-Wg r: Ill é :. Ftw=fig¢§fl i) :: Egg" f .= .- WP> \ The fflJE‘A‘i‘ 5315391in W L“ 71g :5: {Mint} Mi. \ , . , é t: we: M 4) +6? 73,6 __,_ w"uNap“,“wen—“wanna «we We b) (10 points) Predict and give the RMS error for the weight of at student who stands 66 inches tali. : , 1 _ KN“: fl 0 , !.5/ Ru { Zg\ji".5§ it?“ ' {\r " I ‘7 I i ” A; "35" z: a m ) at my? LE Fm Y I" t ,3- 1, W..,>._\.s";m n 1,: m {L if 5 J. ‘ ! g I ' S; 13;“: f"“§',t‘!'i1‘\ii2> f» ’75) - ii “3 a Ting .fihjeai Showing mij I; 01.. ,,.,r.,. ~,)> ,. m"?! it, 1 iw59v+AJ5e“C‘“ii-”WW“ W i c) (10 points) Approximately What percentage of the students who are 66 inches tail weigh more than 140 pounds? f, n {N .. x 1 r H '1 (/1; WW five 5{ up at“ 56”th hit/ttfimtgfitieetfaje #65:“ "j I - ’ \‘I‘ .k ‘ H mm . . W)? it {My “gt”: 9; iii? 5:}; 6 i ' ,3 ft .fm .7: r L 3% ” .3"? ;- W MM {Afjhfifly EVE ’Wfifpnb git f whfijfi r ‘r‘ h t it a. .9' "' {go—{WXHS’ 2~ Wkeitl. We Levitt, 0‘ 9% 0A ‘ik‘tt’ iaigéiifuLQI 556293,;74; “:25,ny £9107 » 1, at: 3-ng tam Meet-WV iifa‘i’ti‘fi, fit a) “W”; w ,. pr . x4 .. , .mrJ,» state! 415%? fies “Vite was. we wrni V EIfiE/j 3-” fl {’3 Question 5 (30 points): Calculate the averages, standard deviations, and the correlation coefficient for each pair of data sets. If you use changes of scale for your calculations, make sure you state What the changes of scale are! Lit-“+- ‘f‘ttili? : 112:“ a)(15 points) A; z 5 “g” X Y K? 469‘ ,. am . 1 3 My“ 59 if: we»{3woaazwwa’ala(wot ... $112133 ,X W‘Wfl‘ll'm“hymn-Mwmg-nwwhwf'wv’mmw “’“‘ w 3 5 a? 5‘" 5 .f z .w : 4: lg: flack Y 1’5“le 54mg 0/44: f6"? MK) jail: fluff/Mi i inwvllml 7 7 ‘5‘? Avfitz/l‘ffixfll ml 596%“- Mm ; , w. MWWMMM TR?- dvm/re at; X? H Affxt’ 5- ' ' J g a . m r: awn-same: {ma—GM Lé M a z: - : m—z: . 52.7Kpr {am La: ' b) (15 points) None that A”: #6 a“; Q: We? \ (1 glide”: fmlléz‘! J39 [was J‘Fdn at we {’llejé film a s‘e‘ffl mt will all}; warlt 3 J’ find Z In: 2mm came Via a it 6?sz ZtW‘f‘ZiJZJfll. N.- “ ‘flffilm lit?“ if? H M “ m ‘ 1'1? M, flnCc’ f if analgélml army; pf” faileji La {:5 If ...
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This test prep was uploaded on 04/14/2008 for the course MATH 1680 taught by Professor Patton during the Fall '08 term at North Texas.

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Exam 1 Key - Exam 1 for Math 1680 Name Date Zffifii/fig...

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