Practice Stat Test

# Practice Stat Test - {x U e{W> i p 5" r l A survey...

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Unformatted text preview: {x U e {W > i p 5):"; r l. A survey conducted by the marketing department of Black Flag asked whether the purchasers of a new type of roach disk found it effective in killing roaches. Seventy~nine percent of the respondents agreed that the roach disk was effective. The number 79% is b) Sample 0) Parameter d) Pepulation e) None of the above 2. The width of metal ﬁle cabinets manufactured at a large factory is approximately normally with a mean of 16 inches and a standard deviation of 0.44 inch. ‘If you randomly sample 17 metal tile cabinets, what is the probability that the sample mean width is less than 15.84 inches? ans: ' 'et a) ?( Efilﬁw - 4v- W. ‘et :2. «are» c) 0.0846 9' m , C).de in s\$§W0m53§3 - elmﬁgbf the above. .. ?(W (V \ q'ci ~— “" \ .. .: to. b in (a? 3. When estimating y for a population with known standard deviation, suppose the margin of error is 5.84. If the conﬁdence level is 95%, what is the standard error of xnbar? a) 1.96 :7 25% gﬁ. 51W 3 \fllg Swag?) set" se :2... a. 2qu 4. In order to take a sample of members of a specific ﬁtness center that has locations throughout the southeast, lrandcrnly select three ﬁtness centers and then contact every member at those three locations. This is an example of a) stratiﬁed sampling b) systematiclsarn ling ampliﬁed d) convenience sampling e) simple random sampling QUESTIONS 5-6: Have you had a business presentation disturbed by a ringing cell phone? In a poil of 446 business men and women, 405 answered this question “yes” and only 41 answered “no” “You Say,” Presentations: Technology and Techniques for E active Communication, Januar 2003, i8 . A is? J?” y ) p 5 3%}; 1 .0 pm g 5. Which of the following represents a 96% conﬁdence intervai for the-population proportion of business men and women who have had their presentations disturbed by cell phones? . J- a) 0.908 :t 01405 f m {SQ a, I Q “a in?) avg mi reform .23 gases“ :3.“ c) 0.908 a: 0.0562 ., , d)405a41 .3: @di‘jLo-exens 405 28 e) 3% 3; «9,0th 6. To conduct a followup study that would provide 96% conﬁdence that the point estimate is correct to within 0.02 of the population proportion, how large a sample . size is required? - KEY] .DSZ . “fin m SLQQLB RNA (0 . Degas 1264 in 1:, _ _ W" _ c) 2637 main: 3 '“ g ‘ Q; a a) 3525 910548 2:: sex. ass a: sea, QUESTIONS 78: A catalog saies company promises to deliver orders placed on the Internet within 3 days. Follow-up calls to over 150 randomly selected customers yields g 95% conﬁdence interval of {0.892, 0.964} for the preportion of talk orders that arrive on ‘ time. 7. What‘isthemarginoferror? W 0 333,2 3: 93.0 '7 3- 4“??? vigil/k ii)” 0 072 c) 0::44 mg. a: {thle‘ W .o it a) 0.928 a. “Q .o an e) Cannot be determined 8. Which if the following is a correct interpretation of the interval? a Between 89.2% and 96.4% of all orders arrive on time. b) ith 95% conﬁdence, the proportion of orders that arrive on time is between 89.2% and 96.4%. c) With 95% conﬁdence, on 95% of the days between 89.2% and 96.4% of the orders Wiil arrive on time. d) 95% of all random samples of customers will Show that 92.8% of orders arrive on time. e) The company is 95% sure that between 89.2% and 96.4% of the orders placed by the customers in this sample arrived on time. .. . ‘ /p\ WW 9. A company packaging 3.4 ounce bags of potato chips maintains quality control by randomly selecting 10 cases from each day’s production and weighing the bags. The 10 cases selected today yielded an average of 3.51 ounces. Which of the following ternis correctly define the numbers in boidtype. N \ a. a) 3.4 is a statistic and 3.51 is a parameter. (a, h) 3.4 is a parameter and 3.51 is a parameter. ' g) 3.4 is a statisticgnd 3.51 is a statistic; gram,“.aww.«..._.m_.__~.;.._.v.>mau .. -- M....J.-_u.,..._,...wummmwm 3.4 is a parameter and 3.51 is gigging) e) None of the above are correct QUESTIONS 10-12: The year 2008 was difﬁcult for the economy and there'were a large number of foreclosures of family homes. In one large community, realtors randomly. 3am]; led 36 bids from potential buyers to determine the average loss in home value. The sample showed the average loss was \$11,560 with a standard deviation of \$1500. 10. Have the conditions for inference been met? ﬂ '2: :75 ‘3 \‘4 w“ M a) Neither randcmnessnnrncnnalidiatrihnhnn are met- ﬁfLWWaI distribution are 130333139 0) Randomness is met but normal distribution is not. d) Randomness is not met but normai distribution is met. e) Randomness is met, but there’s not enough information to determine if normal distribution is met or not. ll. Using the 96% conﬁdence interval{11027, 12093}, which of following is a correct 5 gag}? " decision for a hypothesis test for H0: u = 5000 vs. Ha: u ¢ 5000 with 0L m 0.04? i ' I a) Do not reject the null hypothesis. Data suggests the average loss in home value has changed. b) Do not reject the null hypothesis. Data suggests the average loss in home value has not changed. 0) ‘ eject the null hypothesis. Data suggests the average loss in home value has changed. (1) Reject the null hypothesis. Data suggests the average ioss in home value has not changed. e) This cannot be determined Without calculating a p-value. r‘wi‘ii . 12. Without changing conﬁdence levels, how can you decrease the margin of error for your conﬁdence interval? _amperage.arsenals size; iiigh)-.. crease the sgmple sing?) ri- www.mmhkwﬁs .u . K * and“ c) Decrease the 166a of "signiﬁcance. d) increase the standard deviation. 8) Collect a different sample of consumers who are more sensible. QUESTIONS 1346: Nevada has been one of the fastest growing states in the country for a number of years. Accompanying the rapid grown are massive new construction projects and concern about high pollution levels. in the most recent test of air pollutants, 81 air samples were collected. The study yielded a mean particulate level n 56.3 micrograms/cubic liter of air and standard deviation 2 7.6. ' The EPA must be notiﬁed if the mean particulate level exceeds 55. At a = 0.05, does the EPA need to be notiﬁed? M 13. Which of the following are the correct hypotheses? S; :xg‘zﬁt {‘2 1 a) ﬂea .55 - p Q? m 0 ﬂirt-Hail: =ﬁ.wvs'.lla£s.ll§:3§3 4 3.3. 2‘} “gig a» \$7 ! c) Hg: £2 56.3 vs. Ha: u > 56.3 d) H0:X x 56.3 vs. Hazf> 56.3 e) Ho: 3?“ WSS vs. l—Ia: f >55 14. Which of the following is the test statistic? a) t=l.81 \$19.3 “SET” 15. Which of the following is a correct conclusion? (B (03" 4‘1 \$ 6- D ~ “3 n1 Reject the null hypothesis. Even though the particulate level is above the maximum allow, the difference is not large enough to notify the EPA. Reject the null hypothesis. 1‘ he particulate level is out of control and EPA should be notiﬁed. c) Do not reject the null hypothesis. The particulate level is out of control and ,, the EPA should; be notiﬁed. 0 not reject the null hypothesis. Even though the particulate level is above the maximum allowed, the difference is not large enough to notify the EPA. \$21 0.10 < p~value < 0.15 16. The hypothesis testing procedure above is a) not valid, because we don’t know whether the ﬁll amounts are normally distributed. is) only valid if we use the t distribution to run the test rather than the standard normal distribution. @valid, because 11 a 30 and the central limit theorem guarantees that f N N. d) valid, because the population standard deviation is given rather than the sample standard deviation. ' QUESTEONS 17~18z A study by the National Institute of Health has 8 subjects available to test a new drug, hydroxyurea, that may reduce the number of episodes of pain caused by damaged red blood cells from sickle cell anemia. Using the list of random digits, assign the ﬁrst four subjects to the treatment and the remaining subjects to the placebo. 1 . Blurnenthal " Arms-"ls “Male 5. House w l4 we MW?“ 2. Costello 6. Long 3. Duvall - 7. Pavlicova w thneﬁ- 4. Fan 8. Tang _ lemmas» 81507 27102 56027 55892 33063 41842 8l868 71035 09001 43367 49497 17. The subjects assigned to the PLACEBO are: a),,.ll9s§n.laang,.l3arlisgra...and Tans- M weal-km” éiérielliiigéﬁisliqlhuxalllfreshman???» c) Blumenthal, Costello, Duvall, and Fan. (1) Blumenthal, House, Pavlicova, and Tang. 18. The response variable is a) The presence of sickle cell anemia b) The number of red blood cells 6) Tasmasxdreasrss e;:.;cfij)"””'i‘h‘é“iiﬁﬁibé§: artpisodég‘af‘ﬁan; mWWme-n-l—WW"MWM‘Hmwmwmmw 19. To obtain a sample of students, faculty, and staff at a university, Sara randomly selects 50 faculty from a list of faculty, 125 students from a list of students, and 30 staff members from a list of staff. What type of sampling method did Sara use? /’””afswhma‘\$ﬁed sam lin b) systematic sampling c) cluster sampling d) convenience sampling e) simple random sampling 20. A news release for a diet product company reports:” There’s good news for the 65 million Americans currently on a diet.” Its study showed that people who lose weight can keep it off. The sample was 20 graduates of the company’s program who endorse it in commercials. The results of the sample are probably a) unbiased because these are nationally recognized individuals. _bigngbiasedbntItheymygggldhewmprewaccmate if a larger sample size was used. ﬁshnetsstnernating.thesifsgiixeneggsf d) biased, understating the effectivenessmdll‘the diet. QUESTIONS 21-22: A national survey of restaurant employees found that 75% said that work stress had a negative impact on their personal ﬁves. A sample of 200 employees of a speciﬁc restaurant chain ﬁnds that 136 answer “yes” when asked, “Does work stress have a negative impact on your personal life?” Is this good reason to think that preportion of employess of this chain who would say “yes” diggers from the national proportion of 75%? - .——a—-4..._.. 21. What are the appropriate null and alternate hypotheses? a) Hg: u 275 vs. Ha: u >75 ’0) Ho: u m75 vsHa: u #75 c) He: p m 0.75 vs. Ha: p < 0.75 d) has: 0-75 varnspigﬁ Mr" Ms. W75 vs. Ha; p‘ a 0.7 22. The test statistic is z m «2.286 and p = 0.022. At or 2 0.05, what conclusion should he made? ﬂ Reject H0. The proportion of employees who claim work stress has a negative impact on their personal iife for this speciﬁc chain restaurant is consistent with the nationai survey results. lad Do not reject HQ The proportion of employees who claim work stress has a negative impact on their personal life for this specific chain restaurant is consistent with the nationai survey results. @{eject HQ The preportion of employees who claim work stress has a negative impact on their personal life for this speciﬁc chain restaurant is not consistent with the national survey results. M \\ 1% Accept H0. The proportion of employees who claim work stress has a negative \ﬂ QQ 9 )3: impact on their personai life for this speciﬁc chain restaurant is consistent "‘ .521 wt“ 4's with the national survey results. -. e) Do not reject H0. The proportion of employees who claim work stress has-1a negative impact on their personal life for this speciﬁc chain restaurant is not consistent with the national survey results. 23. When constructing a conﬁdence interval for the true population mean, the conﬁdence interval constructed from the sample data will always be centered around p. a) True 24. A diet guide ciairns that you will get 120 calories from a serving of vaniila yogurt. "lite \. Militia To test this dietary information, Consumer Reports tested 14 brands of vanilla yogurt and 3 found the following 98% conﬁdence intervai: {126.36, 132.21}. If the true number of Q39 ' eateries in vaniila yogurt really is 120 calories, which of the following is correct? a_)‘_q:l:l'§e_gonsumer Reports conclusion was correct. There was no error. \Z/iD “ \3 We; \‘N‘ . B. ..TheMC2ammmemr Renertsscamclusmhﬂaiiﬁmﬂitﬁﬂt- We ‘ \Am a} y 913 . c) The Consumer Reports conclusion was a Type II error. (1) The Consumer Reports conclusion was a Type III error. refs raw” “Edi. ...
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## This note was uploaded on 05/26/2011 for the course STAT 3000 taught by Professor Staff during the Spring '08 term at UGA.

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Practice Stat Test - {x U e{W> i p 5" r l A survey...

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