stat217 s01 test2

stat217 s01 test2 - A phone-in poll conducted by a...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: A phone-in poll conducted by a newspaper reported that 73% of those who called in liked bamboo Donald Trump. The number 73% is what? 2 - The sampling distribution of a statistic is what? a. the probability that we obtain the statistic in repeated random samples . e mechanism that determines Whether randomization was effective @e distribution of val ues taken by a statistic in all possible samples of the same size from the same papulation (9 the extent to which the sample results differ systematically from the truth 3 . The variability of a statistic is described by what? @me spread of its Sampling distribution . the amount of bias present c. the vagueness in the wording of the“ question used to collect the sample data - - d. the stability of the population it describes I L... Which of the following must be true of the probability of an event? ‘ In a series of repetitions of the phenomenon, the probability must eventually add to 1. It must be a number between 0 and 1. c. It must be the same as the probability that the event does not occur. . It must have less variability as the sample size increases. c. .005 but not .001 - d. .001 . mean = $920 and standard deviation = $8.70 c. mean = $92 and standard deviation 2 $87 d. mean = $92 and standard deviation = $870 r A sample of 100 postal employees found that the average time these employees had worked . for the postal service was a? = 8 years. Assume that we know that the standard deviation of the population of times postal service employees have spent with the postal service is 0' = 5 years. A 95% confidence intervallfor the mean time p. the population of postal service employees have Spent with the postal service is used. Which Of the following would produce a confidence interval with a larger margin of error? a. using a sample of 1000 postal employees b. using a confidence level of 90% . using a confidence level of 99% . using a different sample of 100 employees, ignoring the results of the previous sample 8 A national diet company markets a special diet plan which re'quires dieters to use frozen meals prepared by the company. The company advertises that those who follow their plan for 10 weeks wrll lose, on average, at least 10 lbs. A consurher group is suspicious of this claim, believing that the weight loss is, on average, much less. If 1.1. represents the mean weight loss the population of all American adults would experience afterlOweeksonthe l whatisth null hypothesis that the consumer group wishes to test? P am, e ' a. Ham. = 0. to test? . aH.:n=9,2% HO: M; @797. b. H;:“ 9: . 1 1| 9 7‘ c. Hm > 9.2% H“ ’u . @H,:n (9.295 \ 0 ' A medical researcher is curious if the mean weight it .of all college students has changed since 1980. Suppose in 1980 the mean weight was 150 lbs. The researcher plans to examine the weights of a sample of college students in 1995 to see if the mean weight of all college students has changed in 15 years. What is the m hypothesis the researcher wishes to test? . @154; am lbs. Rot M ., {'36 b. Ham = 150 lbs. 7 .u I gt, c. H.2tt < 150 lbs. _ Ha M # . d. Hazu > 150 lbs ll Which of the following would be strong evidence against the null hypothesis H0 in a hypothesis test? ' " a very large P—value very small P-value c. a large sample size d. a small sample size The Columbus Dispatch, the local newspaper for Columbus, Ohio. conducted a poll on the They took a random sample of 1200 voters in Ohio and reported 72% yed would vote for the Republican candidate and announced a margin of error of 13% for 95% confidence in the survey results. At the same time, the Gallup organization poll of 498 voters in Ohio using 1994 governor’s race. of those surve also conducted a those surveyed would v i- 4% for 95%-confidence in the survey results. The information in this box is used in question 12. random sampling and reported 68% of ate for the Republican candidate and announced a margin of error of a. The Dispatch is the local paper. It knows the voters in Columbus, Ohio. better than 'a national organization such as the Gallup organization. Therefore it can report a smaller margin of erro .. I b. The Gallup poll is more honest than the Dispatch poll, because the Gallup organization is a large, national organization. Hence it must report a larger margin of error. e. The Gallup organization is larger than the local group conducting the Dispatch poll. hence it will have a larger margin of error. ' Dispatch po ' margin of error. ll took a larger size sample than the Gallup poll, hence it has a smaller an order is shipped on time if it is sent within 3 working days after it is 'b Poms) received. You audit ‘an SR5 of 100 of the 5000 orders received in the past month. The audit reveals that 86 of these orders were shipped on time. Find a 95% confidence interval for the true proportion of the months orders that were shipped on time. ‘/ " 352* fiU—‘t = .KLoi l.‘fiLo{-F®Cl'.8b) P n too ' w = my 23 a .8530 . . m. M MD 067., cenitolmi that m Proportion otmmogamzm ‘ .. so am that mm shipped on mu LUle heroism “w 7” I ' ' ‘ ' anal .Thesub'ectswere to com dJfl'erent methods of lowenng cholesterol level 1s bemg yzed - j ' _ v ‘.+ giggly to the three treatments, diet, medication and placebo: The response vanahle3 isireductton . b FC‘ ‘73) in cholesterol level. The results are shown in the of printout below. At the 5 A: 1.6Ve1 of significance, how do we__know that there isménough to conclude that the fifths: three treatmentsdifierTWhich treatments difi'er fiom each other? The validity of the results depends on the assumption of equal population standard deviations. How can you tell that we are probably 0K to make this assumption? What is the missing value in the degrees of freedom column 1n the ANOVA table? Source 33 MS F P Factor 660.7 " 330.3 8.91 0.002 Error 18 667.1 37.1 Total 20 1327.8 Individual 95% 015 For Mean Based on Pooled stDev Level N Mean .StDev ———————— -—+ ——————— -—+ ——————— ——+ ---- —— Diet 7 17 286 6.800 ( ----- ——* ————— --) Medicati 7 16 143 6.866 t ————— -—* ----- —-l Placebo 7 4 857 4.220 ( ————— —-* ----- —-) ———————— —-+————--——-+—-————~-—+——-——— Pooled StDev = 6.088 6 0 12 0 18.0 thawing is move“ WM“ “‘- * Pct w W. boost otiticpiittomum Mow “W m mmmlm" J‘b’ WW5 OWN“ titles sum—MPH; bomb P-Votlw [‘3 .>7, ‘ I _/ 'me dim item-Wu (it at end Mdlcumn . ~ :1? m *W‘c 00m 0X9. ax as. \axqg an acne MW M 1- — . Foe elves-nous l5“|8 ,anele emu Glues-non av ‘ Llaboml-s. each) EhTRflCT'HD! This RELMWT whims-11w PM“ “‘5 MtN‘TIltB PQWT-cu'T _ The level of various subsmnces in the blood of kidney dialysis patients is of concern because kidney failure and dialysis can lead to nutritional problems. A researcher did blood tests on several dialysis patients on six consecutive clinic visits. One variable she measured was the level of phos- phate in the blood. An individual's phosphate levels tend to vary normally over time. The data on one patient, in milligrams of phosphate per deciliter ‘ofbloocl,are 5.6 5.1 as 4.8 5.7 6.4 , .bggslfit (a) Calculate the sample mean Tc and also its standard error. if: S. 5E 5. . (b) Use the t procedures to give a_90% confidence interval for this patients mean phosphate level, 81 “15 m Novels. 'whai- H. Y cantrdawe whiva “an (“51 0‘07. &Q(M¥ imatuolfio this patients man phospr mm is new IS / Confidence Intervals ‘ dlBlolonGQfiU-i / ' Variable N Mean StDev SE Mean 90 . 0 it CI phosphat 6 5.361' 0.665 t 4.319, 5.914) . “ ' (-"'——-__ Ho The table below gives the pretest and posttest scores on the Modem Lan- guage Association's listening test in Spanish for 20 high school Spanish teachers who attended an intensive summer course in Spanish. ' 34 3; 1E U. Ho? M “Ma “0 (a) We hope to show that attending the, institute improves listening"- SEE; an appropriate H I u . - H01MZHa‘M7 03) Carry outa test can - - you reject}! at [h 5 . . . 1"“ significance level? ° . e ‘96 Slsnlficance leveI?Atthe liualmsw Paired T-Test Paired T for Cl — c2 "low tun t1 (10+ Wu uh at» the s79 thaivlilru Wan grow is 05mm WWRW v~uatun [5/3. 519‘ mung with MM um (10an how“; (mama's N 20 Mean 27.30 S tDev SE Mean Cl 5.04 ' 1.13 ggf 20 28.75 4.74 1.06 1 ference 20 h,l‘14€;: 3.203 0.716 T—Test of mean difference = D (vs < O): T—Value = —2.02 P~Value - 0.029 I. (7 The Survey of Study Habits and Attitudes (SSHA) is a psychological test - that measures the motivation. attitude toward schoo _l, and study habits of students. Scores range from 0 to 200. A selective private college gives the SSHA to an SR5 of both male and female first-year students. The data for the women are as follows: 108 140 114- 91 180 115 126 92 169 .146 70 115 187 104- . Ca out a test and ' . conclusions. Shire Ho Md Hcc my gm your Ha ‘ M 7;” I; . ‘ i ' ' 01.0th M OK We WMJ+W“Q [S -S TWO sample T for women vs men 11) N Mean StDev SE Mean boi ii— men ‘ 3mm (3 not 2qu bitumm t a men :3 $333 $2613 3:: [g mmau (may WWWth fifib‘ffl 95% CI for mu women — mu men: ( 0.3, 39.4) .“D ‘ a- T-Test mu women - mu men (vs >): T= 2.06 P=0.0 4 DF- 35 . [8 Many homeowners buy detectors to check for the invisible gas radon in Two Sample T-Test and Confidence Interval university researchers placed 12 radon detectors in them to 105 picocurie follows.8 a chamber that expose 5 per liter of radon. The detector readings were as 91.9 97.8 111.4 122.3 105.4 95.0 103.8 99.6 96.6 119.3 104.8 101.7 The distribution is somewhat skewed to u 1 ,u o f the right, but not stroneg enough to forbid use of the t procedures. a ‘ h widtMLQ Is there convincing evidence that the' mean reading of all detectors of m g {S “0+ “‘0 For‘q this type differs from the true value 105? Carry out a test in detail. “I, Sal-chit Ham Ho. . Wuh- ten-1d It's-(M CUM b? WW9?— - T-Test of the Mean 0m Dean mm‘loTSOL ‘5? 1 is [05.11113 WSW“ ' Test of mu = 105.00 vs mu not -= 105.00 I 11C: ‘39 wig {-0 Variable N Mean StDev SE Mean '1‘ ' P radon 12 104.13 9.40 2.71 ~0.32 0.76 ...
View Full Document

This homework help was uploaded on 02/13/2008 for the course STAT 217 taught by Professor Staff during the Spring '01 term at Cal Poly.

Page1 / 6

stat217 s01 test2 - A phone-in poll conducted by a...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online