Stat221 s01 quizes

Stat221 s01 quizes - q-M/lk' _l_ A, Nam Sec: ___/ Stat 221...

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Unformatted text preview: q-M/lk' _l_ A, Nam Sec: ___/ Stat 221 - Quiz 1 1) For the following research issues: — Identify the “observational units” in the study - Identify the variable of interest in the study (make sure you state them as variables) - Identify the variable as quantitative or categorical If you think the measurement is ambiguous, explain why. (a) A comparison of injury rates for several high school spurts showed that ice hockey was the most dangerous sport for high school boys. Est-r3 5' [tr lung S ClrLzCTi‘) \ 3 p (51?; 5 VOL/MLUoLQ ‘7 FJ/i'bfi'IUL-LJ LWVVLQL&S [Wire (3 0'1 pariah-.5) l/V ill/0 l (pl/LCL 6LT.) ULj’C: CJQBW" QM} \ i V _.‘ k ‘ ‘ x 1 till \ l :H\ l \iw \ Lyn“! :5 is, ~\.i~n-i- trim “llaxl Mm in} am i is (b) A new Gallup poll reveals that about one-fourth of the country can speak a language other than English well enough to hold a conversation. i‘ x.../ obs, wee-lg u—T) P601914 La “rm (ELLA/giml/LSL/ Wat‘ch he"? Waste» V'VHVLXXl/UL/k “BEIYMJLVLK c-ay\.:;(>.e.cac, elflLC—i'iigi/L :jv PLO-j— . @ (ii/Marga from WC PK C) n r._./ _2) 2,) You are on the staff of a member of Congress who is considering a controversial bill that provides for government-sponsored insurance for nursing home care. You report that 1128 letters have been received on the issue, of which 871 Oppose the legislation. The representative says “I’m surprised that most of my constituents oppose the bill, I thought it would be quite popular.” In response to this conclusion, comment on a possible bias, if any, regarding voter opinion of the b111, and the direction of the bias. VOW k QP,WLL.C1,L LA agfiwgg r 996% MLL L16... C (a L214" obj (Rf-767W L.{,i_.ch_,-.L Wit 81907 L; C. Le 54 qt -, 1 _’ ‘ r T ' _I = f ' 7 ‘U‘, I r} i . ‘ i _____, Hui/5}” Ac )0 (MM _ VWLS crewm— odmw a5 news A t M magi, bi b I 41. 5; ca’ lei/“La, Wlw “Flu; lLW‘S Vi, {i U: Sine oner- C4,} ill/mu Wm M Tia-{.4010 («£1 029/26- S& . / J . x; r . Inna bur-'- - . .: 'J k 3 , ) igfiqg'jgrg air-i. . / a! I” l‘ ' L J IV I ‘31 ll L' a v v Names: . w" ' " Vw‘) Stat 221 -QuizS h . . "‘ You may use your notes and tables. 1) The average number of days spent in a North Carolina hospital for a coronary bypass in 1992 was 9 days and the standard deviation was 3 days. Suppose that the duration of stays is normally distributed. (a) What is the probability that 10 randomly selected patients will have an average stay ' longer than 11 days? Include a well—labeled sketch of the sampling distribution of average lengths of stay. Vt} 3D 4am, bM pop. 18 norm/Lax! .figjL ‘4'?" - i\'\“'\§>\-r X {mini 0L1tfil€ trawl“ l’hflfl WUU bm/ ll - ~ - - Mata (b) How would this probab1lity d1ffer (larger, smaller, or the same) 1f you calculated the probability that an individual had to stay longer than 9.5 days? (You should not calculate Okay Sf this probability.) Explain why this makes sense intuitively. The ovobaloukt'bj would log \flmjm, Thu? modifies §UM6 mfldtuéhj (Maude We value) 01-6 IS clOSev n Th6 mew/1. When depicteal/Qh.ad€d om a 0va 01. QMMW' hmmlow 019 Vac/Lud WLU \ot mammal mx ‘i’l/LL shard/Mi WM. ‘7- d' ti “(HUVTK “fl “) A , (.A Name: ‘ Sec: 3 Stat 221 — Quiz 3 1 ’ L“ 1) Suppose an advertisement reported that the mean weight loss after using a certain exercise machine for 2 months was 10 pounds. You investigate further and discover that the median weight loss was 3 pounds. (a) Explain whether it is most likely that the weight losses were skewed to right (positive skew), skewed to the left (negative skew) or symmetric. / /""\\ It \.‘_ _ fisngwecw "mi Uri-rij , ye ‘DeobLC__-——~—”“”"j * —""‘ r. l onvgrtbékf MIST kl! i/K (Tu-MUMLTE; inf} V\JC"‘..C/1PUTJ 3”“‘u L"; ‘5‘!" “writ? ' ' I ”=" * l ‘r h'" ‘ \ t ' "' ‘ 7/ l‘il i \\ A} ’ x I puma w p. r/i/g’CL/Oli’li/ ut- pwpm 03+ gamer, guilt/2U .3 \ x K we at ’(fiCU ‘1. RR lit-ii, {,‘jJMLi/L "‘ l :9 I = / -1 (b) As a consumer trying to decide whether or not to buy this exercise machine, would it have been more useful to you for the company to give you the mean or the median? ~ Explain. “Jr/[M pncdmiL Lygfijfif; (1 Wm; me; an 941+ {O { i/lv’lCLl-LC’S H SUCH/l stat-Ct @fCWWLC my; ‘itu lfx’c’TiflUSE" . rte a? CWEWM '\ f / pwuugoq‘i1”6eq magma-H [Fl/Oth if}! tgg'flx’t Lint MM 51. O HOW mums Ibc‘oplg (icon (02¢ 01, ' can (,7 joey» , (- i. .. .f __g . -. l.) l at” . u _ 2) The descriptive statistics below represent the scores on a test of “political awareness” achieved by a sample of college students. Variable N Mean Median TrMean StDev SE Mean score 500 86.60 58.57 75.97_ 90.30 4.04 Variable Minimum Maximum Q1 Q3 score 1.00 658.00 24.61 120.69 (a) The middle 50% of the data is between what two values? .\ 7A— : . ' -\. , C I , b A\ z, MLC/ + [2 L“; (a ? if (7\ fr (it; 3 I _ in, s is e (b) Use the 1.5iqr criterion to determine if there are any mild outliers in these data. _ ‘ 6‘ ' , r ' ' r - Q5 ‘4'?) 6931 L“) {93/ ‘ 7%qu \ “W .1, t (W) <5? (fig. 3 I _ n y _ {:1 .\ _._ _ fl ‘ “77-.-..-..~_.‘/ [ f .5) {My 106:) ‘T‘ {20. ‘9 Ci it! (C 55 ~ 1’7: l/ l M r .5) J i Z/tg'firf " 3:1 {1 LL Luv Y‘u’LCKJ/C is 0: 2598 no “tum—u. at. an rum/it;- (,1/ 1 J: ‘ ‘J . . 4’ <7 ;\\ \\\ / \7?L\ii”if\i’-’)$ iFCflN‘fCJ/L " g :1 av— LC "3 g r ‘ V R“ 4 .... Name: Stat 221 — Quiz 4 D! 1) Suppose that 40% of those eligible for jury duty in a certain community are senior citizens over 65 years of age. (a) Is this number 40% a parameter or a statistic? Explain. firm/Wei. beam WE WW' ‘5 6k waW-[gfig a?) 0L. Jlr101'a3m pLQ, (b) If 12-person juries are selected as simple random samples from the population of ‘ those in this community eligible for jury service, would every jury contain 4 senior. - ' —r _. aran-E- = __.= I E l I v...— , - w -I A - ._ i. 4‘ a . m mu, EA: (Magma: rW The followmg d plot represents the distribution of the proportlon of senlor Citizens 1n g. 1‘ ‘ ‘l L [K K) H M vaj’ Ln". . 1 {E- 500 randomly selected 12—person juries from this population with 40% senior citizens. ‘ 1,13“: ‘ R \‘l x K E E i E E E . a E I E r i E i E ll. E/c-fij’ko g = = E = W r - M a I I I l I ‘i i i i i I E E E E E E E . E E E E E E E .EIEEEEEEI... on, g' _ g h 1.0 flopw-HWL M—flSet/MOK Cahw'fi 1W ? i; 1306:,ij (c) Give each axis an appropriate label. it arrow as J;- (d) Explain what is represented by each dot in the above graph. 1 . ‘ . Qatari (10+ L3 0. 12 WSW Jul/q wfiwwah Saw-0V” - fimg Ephi-r‘ -‘_.i i: l all ‘r'\.( if,” f‘ '1; EEH‘ l \‘l ‘ '__x I"? '. 'El E- . ‘- I hr} li."‘~/ 5.. (e) Suppose that a particular defendant in a jury trial has reason to believe that senior citizens would be more sympathetic to her than younger jurors would be. Suppose that the jury selected to hear her case contains only two senior citizens. Would you Say this is a common or an unusual outcome? Explain your answer. 77415 {601}? arm) WLLLSE/Lou because mjwwj urn/aw be -l {w}! Ctr/056V] and % “fl/U0 SMLoE/ 0&1ng '\‘" M a? [Lu/L WOE/rtc‘l W Motor Ol/_ dbl/moi: L MW e wizan WWW’W IS PM” Com on _ mu; (“flair-J}. 11‘. .‘jJ-c < I‘La. I . l‘. . J {J Spring, 2001 W? /K in .. j 'y Name: Sec: \j Stat 221 - Quiz 2 fl 1) For the following research issues indicate whether you would use an observational study (including survey) or an experiment to answer the question and briefly explain why (include why the other type of study is not appropriate). (3.) Does a high level of salt in the diet lead to higher levels of blood pressure? i .21)"; 8X ‘IWT fl} ‘bvt EDI/Lid Halli “fl/Lt (swpa) sea/1c. msw+lfigylow Scoot efflua Cari/Lay (/0ng 8&1“ mm toga Levels 0? Saw .m oparvrwmm wldmbcug‘t hard because m dawn—(cm o{’— “ll/ugh $6th may .0 m new Rome» Eeng mm wan/Ltd b4 macaw-a4: _ l‘f)‘ ! ~: L ‘J {ti-(Lt g_)\_ a ‘-£_-*lf Rial. ‘I I (b) Do states with more liberal concealed weapons laws have lower crime rates than states with more conservative concealed weapons laws? DbgfiV’VQflDflW-i “‘“’ it would \x appropvicdre tin owed/Vt: the, WWVW ‘ Struts Mmth laws and outcan awn/La vases vagug WST‘OK‘J‘QS W/o mac laws. (\[ou wvuctofir pohcmm J an fixpcwm‘l— mag «WW5 no Way +0 akttl/ WWW or firms law's M lcbeval 01/ nor. ,Q;T\J-;;—,,a ‘71. m, 2) The following were some of the variables I measured on you with the WebCT survey (a) your heights ‘ (b) number of siblings (c) amount paid for your last haircut (d) amount of change in your pockets (e) your guesses of my age For each variable, do you think the shape will be symmetric, skewed to the left (negative skew) or skewed to the right (positive skew)? Feel free to defend your choice and/or sketch a graph. (a) S mwmj’vi L, / 5 ‘ - ‘ - fl LILAC t (b) gwmmcn I majomnj pmmaby have 2 “fig/ix? _ - dot/it ’\ (C) frat/Li ? SGM.PCDPUL 1)ch RUN-*1 )DMJ‘ V/ L _________H (d) ‘i’lrLQ, * Wart 0cm lover—a. 9/ J \ 1 (am ‘7'?) W fl‘cJ‘ var r moSr Mam film/ac: \fDWt \[ow'tg‘ J ‘ 1K. A I S" i/\ k (t (“d af’ ?“i'u A ‘ Names: Sec: . Stat 221 — Quiz 6 332/ For this quiz, you may use your books, notes, and one other person. Turn in one quiz for both of you. We have learned the following procedures (a) One sample proportion z—test (b) One sample proportion z-interval (c) One sample mean t-test (d) One sample mean t-interval (e) Two sample proportions z-test (f) Two sample proportions z-interval (g) Two sample means t-test (h) Two sample means t-interval (i) Chi-square test for independence (j) ANOVA test for several means 1) For each situation below, identify the appropriate inferential procedure from the list above, and if a test of significance clearly state Ho and Ha. If you think there is any doubt in your choice, explain your reasoning. (a) A university anticipates that next year there will be a need to house 47% of its undergraduate students. The student newspaper conducts a random sample of 50 students who claim to be returning next year and wants to know if there is significant evidence that the university should increase their estimate of the overall proportion who need housing. is (WW-j WVW C’s/flak 053 Cu pvopmfhm \Sb L\ l’lll .1 ‘l (b) Three major radio stations service a large metropolitan area. An independent marketing firm classifies listeners as “young” and “mature” based on their age. The firm surveys one hundred ratio listeners and asks which station they listen to most. They want to know if there is a relationship between the listener’s maturity level and which station they prefer. - ' ‘ W Lye, HAW 0‘ L H72 SH: Mam V/pzr TU . ‘Ha ‘ l WLOL‘h/L/Lle—j ‘/ WM ctr Sam’er '- (c) There are approximately 30,000 companies that are members of a charitable collaborative across the entire country. A random sample of 250 of these companies is taken and it is found that 210 of the CEO's and 8410 of the 15,000 junior executives hold at least a master's degree. You are asked to estimate how much higher the population proportion of CEO’s with a master’s degree is than the population proportion of junior executives. ' Sf M' ‘ H bun/W knaStoVS C‘E/O‘S ‘ o ' MW ‘ ' War f Ox ‘ a; W L u Wig ML- Names: Stat 221 - Quiz 5 You may use your notes and tables. 1) The average number of days spent in a North Carolina hospital for a coronary bypass in 1992 was 9 days and the standard deviation was 3 days. Suppose that the duration of stays is normally distributed. (a) What is the probability that 10 randomly selected patients will have an average stay longer than 11 days? Include a well—labeled sketch of the sampling distribution of average lengths of stay. (b) How would this probability differ (larger, smaller, or the same) if you calculated the probability that an individual had to stay longer than 9.5 days? (You should not calculate this probability.) Explain why this makes sense intuitively. ...
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This homework help was uploaded on 02/13/2008 for the course STAT 221 taught by Professor Lund during the Spring '05 term at Cal Poly.

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Stat221 s01 quizes - q-M/lk' _l_ A, Nam Sec: ___/ Stat 221...

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