This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Exam #2 Stat 251
Winter 2006 Namt Solve the problem. 2. ‘ (i) We know that the sam devration. The center ' g center wants to determine the proportion of business students who
ave personal computers (PCs) at home. If the proportion diff
2: 2 . <o= .445 ers from 35%, then the lab will
odify a proposed enlargement of its facilities. Suppose a hyp othesis test is conducted and the test
, statistic is 2.6. Find the p—value for a two—tailed test of hypoth ?“Vﬂ\=(Z.>2il0)= 7.>.‘l463 esis.
.S‘.“\’l‘>2> ’ .0047 * 1 = .0044
B) .4906 n = (7, xiii)ng ml : 3.2.17, ’4 7:172
(5 2. B) 161 C) 3 @3
n: L} 000 5) Many people think that a national lobby s successful fight a gainst gun control legislation IS
7:) _ )160 gbﬁﬁﬂectmg the Will of a minority of Americans A random sample of 4,000 Citizens yielded 2 250 who
) #356 = are in favor of gun control legislation. Estimate the true proportion of all Americans who are in
favor of gun control legislation usin a 90% confidence i terval.
2.42407, :Wis «Stole I [.mqg,§(.smsvr.+316)i = Bezel 0,011”!
: 4 2,1 5 b B) .4375 2 .4048 D) .5625 1 .4048 .5625 t .0129
« J 31
Kg“) @4375 2 .0129 We have created a 99% confidence interval for p. with the result (11, 16). What conclusion will we 6)
makeifwetestH0:u=21vs.Ha:uz21at0L=.01? Hoax/(22‘ \%‘0=13.€=§
A) Fail to reject H0. ‘H‘A imkll
@Reject H0 in favor of Ha. u g ' o ‘ Zia/:44 ‘l' = 2.5?)
C) Accept H0 in favor of Ha. D) We cannot tell what our decision will be with the information given. A—1 \\ V0 2\ m“:
‘i 3)C. N B A randomly selected ball bearing has a diameter greater than 3.1 millimeters? ZS LlS = Li’.5"%.l Jﬁ 4'4 4.5—2.5 : 2. ‘0'7
A) 0.6889 B) 1.5 C) 0.4429 .7
h ‘ 250 8) A univerSity IS conSIdering a change in the way students pay for their education Presently, the
X 1 H I \ students pay $16 per credit hour The univerSity is contemplating charging each student a set fee of per student per quarter using a 99% confidence interval. ii.\:2.ecb(%) = \Hli .515 A) 14.1 1 .024 B) 14.1 1 .016 C) 14.1 1 .247 4.1 t .375 @5811 ppose we wish to test H0: p. = 34 vs. Ha: u < 34 Which of the following possible sample results gies the most evidence to support Ha (i.e., reject H0)? Assume n=30. x=32,s=6 B)x=33,s=8:‘/\ @=39,s=2
/ :—\~%73 jﬁglyf ;~ la . W5 .' 6 “7 a ' _‘
~10) The amount of corn chips dispensed into a 15—ounce bag by the dispensing machine has been C)x=31,s=42;(\ 7 1' l5 identified at possessmg a normal distribution with a mean of 15 5 ounces and a standard deViation
O : O . g) of 0 3 ounce Suppose 100 bags of chips were randomly selected from this dispensmg machine
h = ‘00 Find the probability that the sample mean weight of these 100 bags exceeded 15 6 ounces
2. _ " \5'S—lglb w ‘32) ‘4;
MX ‘093’ thew“ 4.93 as 0" “MK. 1 5 .s x “z . 7) 6 D7; A) .1915 @pproximately 0 C) .3085 D) .6915
/ ‘
\0 site, the wind speeds averaged Q = 14.2 mph, with a standard deviation of s = 3.5 mph. To : 5 determine whether the site meets the organization's requirements, consider the test,
Ho ",Ll, T '5 H041 = 15 vs. Ha: p. > 15, where it is the true mean wind speed at the site and a = .05. Fill in the
HA ' 11> l 5 blanks. "A Type I error in the context of this problem is to conclude that the true mean wind speed
0" ; \ 08 at the site 15 mph when it actually 15 mph."
#exceeds; exceeds —B)equals; equals 'C) equals; exceeds xceeds; equals 7)D @3832 seconds B) 536.8 seconds @3613 seconds D) 558.7 seconds
TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. Answer the question True or False. ’ 15) As the sample size taken gets larger, the standard error of the sampling dxstrrbutron of the sample ) T
mean gets larger as well.
@ The smaller the p—value in a test of hypothesis, the more the results dlsagree W1th the null W l:
th 7 ’
hypo e519 T312 yr 21‘ . rpret the
F : ‘Ob (segult in the context of the problem (1 sentence). 5
___,_ 7 ‘ v _ . 2 . D
we 9’ z= .smfbs‘ ; 1332. \ 4
2‘ ‘ w M. /__.. = LDD— J1
61" .lt7 WEE'5’) vows "m
l’ we tpam TD ref“? Ho m tint
exqmﬁmme Mex <>«—.\O. L1?)  Ther ﬁfmgﬁgjdgym euxvlmm MM X4 dee—WCts 06mch MQV‘FCHW ~WWCW1 <25! mutomm W, Wt \n W ...
View
Full Document
 Winter '06
 staff

Click to edit the document details