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A 4 ‘ / au | 74a } ATL IOs Period f Chapter 8 Test Review Name Qa... Section |: Multiple Choice Select the best answer for each question. 1. The Gallup Poll interviews 1600 people. Of these, 18% say that they jog regularly. The news report adds: The ts at a 95% confidence level.” You can safely poll had a margin of error of plus or minus three percentage poin a conclude that i: a, J =, 16 SUC E “= 1 C 5 (a))95% of all Gallup Poll samples like this one give answers within +3% of the true population value. {b}-the percent of the population who jog is certain to be between 15% and 21%. “te).95% of the population jog between 15% and 21% of the time. “(d} we can be 95% confident that the sample proportion is captured by the confidence interval. fe) if Gallup took many samples, 95% of them would find that 18% of the people in the sample jog. 2\ The weights (in pounds) of three adult males are 160, 215, and 195. The standard error of the mean of these three weights is pcr © —_— 190. 2788 Sx 7 27.83) 22:13. Grn SE x 727.6395 1C.0701 Te 3. In preparing to construct a one-sample t interval for a population mean, suppose we are not sure if the population distribution is Normal. In which of the following circumstances would we not be safe constructing the interval based on an SRS of size 24 from the population? a A stemplot of the data is roughly bell-shaped. — IC LI JCeCSN F ‘tb) A histogram of the data shows slight skewness. hg ede 2 Rat (c)A boxplot of the data has a large outlier. npPIyY and fhe (es cvuthels ‘td) The sample standard deviation is large. te) A Normal probability plot of the data is fairly linear. 4. Many television viewers express doubts about the validity of certain commercials. In an attempt to answer their critics, Timex Group USA wishes to estimate the proportion of consumers who believe what is shown in Timex television commercials. Let p represent the true proportion of consumers who believe what is shown in Timex television commercials. What is the smallest number of consumers that Timex can Nua to guarantee a margin Deen ee al ? p yt ' f j se of error of 0.05 or less at a 99% confidence level: a a UP ) iy ¥ ode es _ —~ | / Late \ Oba Oo 2. 7 2 th), 00 ) 650 ; :. Be ae VA, MeX4 icv s LAgree is - C. Te).750 ofa population with unknown population mean 5. You want to compute a.90% confidence interval for the ld use for this interval Is standard deviation. The sample size is 30. The value of f* you wou on ee ert, (6)1.699. Viz 30 d Td} 1.96, + ety pa , sh i nye 29) = | | ! in his listening area wh 6. Aradio talk show host with a large audience is interested in the proportion Pp of adults In | . owing question to Nis think the drinking age should be lowered to eighteen, To find thi ut, he poses the foll a in light of the fact that eighteen listeners: “Do you think that the drinking age should be reduced to eighteen | 3 ‘he Aa year-olds are eligible for military service?” He asks listeners to phone in and vote “Yes " if they agr as ——— age should be lowered and “No” if not, Of the 100 people who phoned in, 70 answered “Yes.” Which 0 following conditions for inference about a proportion using a confidence interval are violated? Lesh CNG |, The data are a random sample from the population of interest. VolUu NI TAVy l|. The population is at least 10 times as large as the sample, / III. nis so large that both np and n(1 — f)are at least 10. / 7. A90% confidence interval for the mean Lt of a population is computed from a random sample and is found to be 9 + 3. Which of the following could be the 95% confidence interval based on the same data? W922 N$6lileyy 32 99K SE jnvncim (IF 6 1) 7 645 ‘tb)9 +3 — 3.574y — 944 = |i Goss SE 4, one mune (1-195 9 /)= 1,96C ei oh ‘e) Without knowing the sample size, any of the above answers could be the 95% confidence interval. 8. Suppose we want a 90% confidence interval for the average amount spent on books by freshmen in their first year at a major university. The interval is to have a margin of error of $2. Based on last year’s book sales, we estimate that the standard deviation of the amount spent will be close to $30. The number of observations required is closest to a =< Section Il: Free Response our Show all your work. Indi methods as wel i Indicate clearly the methods you use, because you will be graded on on the accuracy and completeness of your results and explanations. the correctness of y es allowed to enter 11. The US. F ». FO — | rest Service is considering additional restrictions on the number of vehicl ; le of 150 visitors if tl Yellowstone Nati ational Park. To assess : public reaction, the servi ks arandom sam favor the proposal. Of these, 89 say “Yes.” oo (a) Construct and i t and interpret a 99% confidence interval for the proportion of all visitors to Yellowstone who the restrictions. Stare We want te Cat mate P= tive (> Pulabon flotottir a” es fava Fuk (97 VATE COS) +c vellcwstare Who Woy | Say tyre ara G4 cofdene level Plan! one Somfle 2 interval for 0 LE Cofdidicnts are Met Random! & tandem somle oF (50 v's ely was Stated / oye ‘NeisoLllio oO al V's 1015 te yetwstene Polk Vv Lal je Couts | NP = (So (=) Gt > 10 let a. L N(i-0)2 156 (12! ) xe! | & O% , ee Lb faP 2 sat (xed, Nz 15¢, Cleve! = 494) Becalse tneve cle vaiues IOwer tray) , 50 in tee cont ance Tnreval the US Feress Selvite Can} Conavuae That Mere tuan hale of tne VIS, to Vellewstene p/atieng | Palk Ffuver tre Pic PeESa/ (,Ufo,. 647) lA/]e 0, fe 4 9 ‘Jo Cel f ident z hat tyre tlue Po PUlation p(cleHen of att vis'tB ve plu lg Say that tue fcr tre Lestithiens berveen .4ho and + 677, pies Tp: 12, How many people live j N South Afri over 700,000 South Africa frican households? To find out, we collected data from an SRS of 4 people livingin ah N students who took part in the CensusAtSchool survey project. The mean number of Bin 2 household was 6.208; the standard deviation was 2.576. (a) Is the N Ormal/Large Sample condition met in this case? Justify your answer. A8 out of the 2.576 —— (b) Maurice claims that a 95% confidence interval for the population mean is 6.20841.96 Explain why this interval is wrong. Then give the correct interval. |, Maurice used 7* fol 15 de Chiiwker Shceuld Use L* an + 4 Li ¢ od 2, U5€§ Jae and Snoul) be IN ot Jug Ce eee wong he 
