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Unformatted text preview: Stat 145 Name I .
Midterm Exam — Version A Recitation Time T 5’\ l 3 ?,Q
Winter 2007 3
70 Circle your TA’s name from the list of names below: Marian Frazier
Mallik Rettiganti Candace Berret t ’
Stephanie Jones Joe ' upreanin There are a total of 40 points on this exam.
**Multiple Choice** (2 points each) Please circle the best answer. Mary Hickey
Don Turchany 1) Which statement about the standard deviations is FALSE? 5 can never be zero.
5 is a nonresistant (sensitive to outliers) measure of spread. as is the range
d) s is measure in the some units as the data. 2) An opinion poll contacts llol adults in the United States and asks them. “Which political party do
you think has better ideas for leading the country in the twentyfirst century?” In all, 696 of the 1161
say, “The Democrats.” The sample in this setting is a) all 225 million adults in the United States. b) all registered voters. tilie 1161 people interviewed)
t 1e 696 people who c ose the Democrats.
3) A balanced coin is flipped lOO times. By the law of large numbers: 2]) There will almost certainly be exactly 50 heads and 50 tails, b) If we got 100 heads in a row, almost certainly the next ﬂip will be a tail. c) For the 100 flips, the probability of getting lOO heads equals the probability of getting 50
heads. d) It is absolutel ' impossible to get a head every time. 4) You look at real estate ads for houses in Sarasota, Florida. There are many houses ranging from
$200,000 to $400,000 in price. The few houses on the water, however, have prices up to $15 million.
The distribution of house prices will be a) skewed to the left.
c s ewe o e rig t.
5) For two events A and B, P(A) : 0.5 and P(B) : 0.2. Then P(A or B) equals a) 0.10, ifA and B are disjoint.
b) (l. [0, ifA and B are inde endent.
C) 0.70, it A and B are is 0i andlB are independent. . Bagel}, ‘ o) A recent General Social Survey asked subjects ifthey supported legalizing abortion in each of seven
different circumstances. The percentage who support legalization varied between 45% (if the woman
wants it for any reason) to 92% (if the woman’s health is seriously endangered by the pregnancy.
This indicates that res onses canvge‘pend greatly on t e question wording.
c) the sample must not have been randomly selected.
cl) the sample must have had problems with response bias. 7) To make a boxplot of a distribution, you must know
a) all of the individual observations.
b) the mean and the standard deviation. c) the median and the inter uartile range.
.f d) the fivenumber summary. ) 8) A sample of households in a community is selected at random from the telephone directory. In this
community, 4% of households have no telephone and another 35% have unlisted telephone numbers
The sample will certainly suffer from a) nonresponse.
c) voluntary response.
d) false responses. 9) To display the distribution of grades (A, B, C, D, E) in a course. it would be correct to use
a) a pie chart but not a bar chart.
b) a bar chart but not a pie chart. Cit era ple C 1a or a ar c art. neit ier a pie c an or a ar chart. 10) An lntemet poll conducted in the UK. by Netdoctor.co.uk asked individuals to respond to an
“Emotional health survey.” There were 1000 volunteer respondents. Based on the results, the British
Broadcasting Corporation (BBC) reported that “Britons are miserableﬁit’s official." This conclusion
reﬂected the poll responses. of which onequarter feared a “hopeless future." one in three l‘clt
“downright miserable," and nearly one in ten thought “their death would make things better for
others." Which of the following is NOT correct about why these results may be misleading? a) Many people who access a medical website and are willing to take the time to answer this
questionnaire may be having emotional health problems.
b) Some respondents may not have been truthful or may have been Internet surfers who take
pleasure in filling out a questionnaire multiple times with extreme answers.
c) The sample is a volunteer sample rather than a random sample.
C d) )lt’s impossible to learn useful results about a population from a sample of only [000 people. Page 2 ***For questions 1113, you cannot get full credit unless you show your work. Partial credit will be
granted based on worked shown. Make sure to show formulas and calculator inputs where
appropriate. 11) (4 points) A maker of fabric for clothing is setting up a new line to “finish” the raw fabric,
The line will use a dyeing cycle time of either 30 minutes or 40 minutes and a temperature of 0 either 1500 or 175° Celsius, An experiment will compare all combinations of these choices.
/’ Identify the following: 21) Experimental unili
r El 1C r
\/ "/ b) Factor(s): lamb)! (iii a (H («W/SK ‘iit,:§\j«\\ , ‘yﬁ LC {W91fquxM‘Q
c, r, rams/ tee C (so mxmks/ mg C) UIC “trunks/[SC (f? Lie rrtimoRV]7¢C
(1) Response variable: i w F .
rm dim) git/$6365 sake? c) Treatments: Li $M>93mgqrsx+$ﬂ 12) (4 points) The bar chart below is based on a study investigating the factors that inﬂuence
alligators’ choice of food. Researchers classified the primary food choice (in volume) found
in the alligators’ stomachs as fish, invertebrate (snails, insects, crayfish), reptile (turtles, baby
alligators), bird, or other (amphibian, mammal, plants). Primary Food Choiceof Alligators N
O U
u,
m
u
I
ll
U
h
8’. , .
Fish Invertebrate Percent within all data. a) 15 primary food choice categorical or quantitative? Exglain your choice. h
{ Kickbag’, {Ax ( (\~33Q t.) :7 x.‘ g A H " .;:r{\ ﬁg f—X 'q~\."\/\;»\:\> k (r k; ,0 g t ~33
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/ 0 b) Appﬁiximately what percentage alligators chose invertebrates as their primary food? , e C\ 0/
(If (1. x (\"rt H.J\\t\ o Q
f? —2 Page 3 ——O I3) (12 points) Preventable chronic diseases are increasing rapidly in Native American
populations, particularly diabetes. Gilliland et all examined the diabetes issue in the paper
“Preventative Health Care among Rural American Indians in New Mexico” (Preventative
Medicine, 1999, Vol. 28, pp 194—202). The data are presented in the table below: Diabetic state : Diabetes N 0 diabetes Total
.5 Less than HS 33 218 251
8 HS grad 25 389 414
{:1 Some college 20 393 413
a College grad 17 178 195
Total 1 95 1178 1273 If we select a person at random from this study:
a) What is the probability that the pewﬁs than a hi gh scnool diploma? ,2»sz '. LA 0\ 7 9
J37 ‘9
b) What is the probability that the person has diabetes? “(15* : Qﬂﬂtlé / 4 3‘7 1.; c) What is the probability that the person has diabetes and has less than a high school diploma? / Q) A N
J T. ialg d) What is the probability that a person that has less than a high school diploma has diabetes?
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as) 41 e) Using your work above, show that diabetic state and educational level are not indeﬁnﬁiatwv Z \X’ («Ugh g (Ni Ra lAé‘xet‘ggznlembT PC: teasing), asy : Q{.lwotlc§/A>Q~CW weenamasms (Twelve; , new 1 Que/m5
«we. as? ' " cialﬂ‘d 0 Can you think of a lur ing variable that would help explain wh diabetic state and educational level are associated? Explain. ,1"
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 Winter '07
 JustinKubatko
 Statistics, Diabetes, Bar chart, primary food choice, diabetic state, Food Choiceof Alligators

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