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Unformatted text preview: Stat 119 Qniz 6C Name:
Red id: Use the following to answer Questions 13:
A 90% conﬁdence interval for the proportion of drivers who change CD5 while they are driving is {0.633. 0.667) 1. (2 points) What is the point estimate of the true proportion of drivers who change CD5
while driving? (i point) The margin of error for the conﬁdence interval is: .saa retire $0 is m3” Answer
3. (i point) What is the best interpretation of the above intervai?
A. 90% of the time the sampie proportion of drivers who change CDs while driving
wili be within the intervai.
B. 90% of the time the true proportion of drivers who change CD5 while driving will be within the interval.
C. We are 90% conﬁdent that the sample proportion of drivers who change CD5 ._ whiie driving will be within the intervai. We are 90% confident that the tree proportion of drivers who change CDs while ' driving wiii be within the interval.
Use the following information for problems 47 “a
A survey conducted at SDSU interviews a random sample of 267 female students and 190 P :2 __
admitted to dieting within the past 12 months. " 4. (3 points) Construct a 99% conﬁdence intervai for p, the population proportion of female
SDSU students who have been on rant i: Meet ens a. car 6 NW; 333$) 5. (1 point) Give a onewsentence interpretation of yo r conﬁdence intervai. an M; W gig g W? rite. earth sg fame anger gm _ a3 mm mvg .. a éégvg 2‘ es risen. are, a, éi: ﬁr?“ wig 6. {2 points) How many female students wonid we need to survey in order to reduce the
margin of error to 0.03? m 5 mi :3 is”; a» is. 7. (1 point} Suppose the researcher decided that he wanted to obtain a shorter conﬁdence
intervai than the one caiculated above. This couid be accomplished by:
A Using a lower level of conﬁdencee’
Using a smaller sampie size. X B. C. Using a higher levei of confidence. sf D. Both A) and B) %
Answer: Use the foliowing information for problems 89
An article in the Annals ofﬁte Association of American Geographers revealed that only E13 of 337 randomly seiected residences in Les Angeies County were protected by earthquake
insurance. Do the data provide sufﬁcient evidence to show that less than 40% of the residents of
Los Angeles County are protected by earthquake insuraaee‘? Use a 0.05 Eevel of significance. 8. (1 point) Give two assumptions that must be met in order for a hypothesis t to be valid yet? We eegeito “ gag
sagaeete at Q. mt at? eeeetaase a. 9. Conduct a hypothesis test:
I. (2 points) State the nut} and alternative hypotheses. II. (2 points) Caicuiate the test statistic. is: ‘Eggg “" 'iég E .... x
u 3;: ‘ gﬁegg " .. 5 2 {is 2“ HI. (2 points) Caiculate the corresponding pValue. 3" Vales e; We eel, tats 3 .eeeg ...
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This note was uploaded on 05/04/2008 for the course STAT 119 taught by Professor Helen during the Spring '07 term at San Diego State.
 Spring '07
 Helen
 Statistics

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