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Unformatted text preview: A phonein 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 Pvalue
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
PVotlw [‘3 .>7, ‘ I _/
'me dim itemWu (it at end Mdlcumn . ~ :1? m *W‘c 00m 0X9. ax as. \axqg an acne MW M 1 — . Foe elvesnous l5“8 ,anele emu Gluesnon av
‘ Llabomls. each) EhTRﬂCT'HD! This RELMWT whims11w PM“ “‘5
MtN‘TIltB PQWTcu'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 ‘
dlBlolonGQﬁUi / '
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 TTest 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 ﬁrstyear 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 TTest 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 TTest 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, Salchit Ham Ho. . Wuh ten1d It's(M CUM b? WW9?—  TTest 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 ...
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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.
 Spring '01
 staff

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