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**Unformatted text preview: **Stat 210 Exam Two Read these directions carefully. Take your time and check your work. Many students do not take enough time on their
tests. Each problem is worth four points. You may choose exactly question to omit by writting "omit" in the answer blank.
If you do not omit any, or omit more than one, all will be graded. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Determine whether the events are disjoint. 1+ :6 055,- \J 16 ha 5 Q. S hu “3 B
1) Get stung by a bee. HA, 2.2. 0/1 1)
Get stung by a wasp. h ‘3 ‘0 d a -
A) Yes w 0V MJ 0:9 {3 - C) Both yes and no
Is Event B de endent or inde endent of Event A? A
2) A: A mosquito lands on your arm. 2)
B: '. get a mosquito bite.
wlependent B) Independent C) Rebublican D) Democrat
Find the indicated probability. ( 3) Find the probability of correctly answering the first 3 questions on a multiple choice test if random 3)
- -- -—-—guesses—a-re—made-and-eael+quesﬁenhas—6—pessible~ans A - . 1 1
A) 2 B) —2- LI ‘3 D) 75
4) The table below describes the smoking habits of a group of asthma sufferers. 4) E5
Light Heavy Nonsmoker smoker smoke Total as ‘91.:
eﬁT"a‘to If two different people are randomly selected from the 991 subjects, find the probability that they
. are both heavy smokers. Ro . - a to six decimal places.
A) 0.001796 0.007451 C) 0.007531 D) 0.0001352 Find the indicated probability. Round to the nearest thousandth. D
5) A sample of 4 different calculators is randomly selected from a group containing 18 that are 5) defective and 40 that have no defects. What is the probability that at least one of the calculators is defective? .
A) 0.215 B) 0.774 C) 0.180 D) 0.785 Find the indicated probability. Express your answer as a simplified fraction unless otherwise noted. C
6) The table below shows the soft drinks preferences of people in three age groups. 6)
cola root beer lemon—lime of age.
1 2
A)? B); Evaluate the expression. 7) 10% 7)
A) 3 B) 5040 D) 240
. SolveJheprohlem. ,. mmmm ‘8
8) How many ways can an IRS - . o 'tor select 3 of 9 tax returns for an audit? 8)
A) 729 ' B) 84 ‘ C) 6 D) 504
ci— a . 7
(3 1. ,__...
R 3 '54—“ i ‘
9) A pollster wants to minimize the effect the order of the questions has on a person's response to a 9)
survey. How many different surveys are required to cover all possible arrangements if there are 11
questions on the survey?
A) 11 B) 121 C) 3,628,800 @39,916,800
9 2—. l l ‘.
i l H
Identify the given random variable as being discrete or continuous. B
10) The exact braking time of a car 10) A) Discrete @ C) Public Determine whether the following is a probability distribution. If not, identify the requirement that is not satisfied.
11) 11)
P(x)
0.07
0-15 06H; +0 0 (\C
0.20
0.41
0.17
A) Probability distribution. B) Not prob. dist; does not add to one
C) Not prob. dist; probabilities greater than one D) Not prob. dist: probabilities less than zero x
0
1
2
3
4 Find the mean of the given probability distribution. C.
12) In a certain town, 30% of adults have a college degree. The accompanying table describes the 12)
probability distribution for the number of adults (among 4 randomly selected adults) who have a
college degree. x P(x)
0 0.2401
1 04116 L
2 0.2646 l‘VQFS fed LL! 7'
3 0.0756
4 0.0081 7
A) u=1.10 B) u=1.44 C) u=1. O D) u=2.00
Provide an appropriate response. Round to the nearest hundredth. C '
13) Find the standard deviation for the given probability distribution. 13) B) a = 2.90 D) (r = 2.52 Answer the queshon. A
14) Focus groups of 15 people are randomly selected to discuss products of the Yummy Company. It 14)
is determined that the mean number (per group) who recognize the Yummy brand name is 12.5,
and the standard deviation is 0.58. W_____ould it be unusual to randomly select 15 people and find that fewer than 9 recognize the Yummy brand name?
W X M U‘iual Fmge; ins—"40.5) w \‘l.§+?—(O.5l Assume that a researcher randomly selects 14 newborn babies and counts the number of girls selected, x. The
probabilities corresponding to the 14 possible values of x are summarized in the given table. Answer the question using
the table. Probabilities of Girls
x(girls) P(x) x(girls) P(x) xigirls) P \ DWNH 15) I; 3 A) 0.061 D) 0.122 Provide an appropriate response.
16) Suppose you buy 1 ticket for $1 out of a lottery of 1,000 tickets where the prize for the one winning ticket is to be $500. What is your expected value? ,
A) —$1.00 B) $0.00 C) -$0.40
. goo % 00 v3 0 ,_
UNA W aSO—\.00 4- ”0150
0 Determine whether the given procedure results in a binomial distribution. If not, state the reason why.
- from a box of 40 marbles (20 purple, 12 red, and 8 green) one at a time ﬁNot binomial: the trials are not inde endent.
B) Procedure results 1n a binomon.
C) Not binomial: there are too many trials.
D) Not binomial: there are more than two outcomes for each trial. 11 17) A Assume that a procedure yields a binomial distribution with a trial repeated 11 times. Use the binomial probability
formula to ﬁnd the probability of x successes given the probability p of success on a single trial. Round to three decimal "places.
18) n:5,x=2,p=0.70 A) 0.700 B) 0.198 D) 0 464 bums/14 pd1c('3 C9 70/ 2\~ {313 Find the indicated probability. Round to three decimal places.
19) Find the probability of at least 2 girls' In 6 births. Assume that male and female births are equally likely and that the births are independent events.
A) 0. 234 B 0.656 C) 0 891 D) 0.109 PLa’t least 3:100 11.. Fiat Mose ane\ _—_- l-lom<1M UH“ {6 (9.5 Find the indicated probability. '
20) In a survey of 300 coll ; : .3 aduates,.orted that they entered a profession closely related to their college major. ”we survey bjemandomly selected without replacement for a follow—up survey, w a 1 ability a 3 of e entered a profession closely related to
their college major?
A) 0.0637 B) 0.176 blAOMPA€ (8'1 O‘Sé/ ’)3\
Solve the problem. 21) On a multiple choice test with 17 questions, each question has four possible answers, one of which is correct. For students who guess at all answers, find the mean for the number . e ect answers.
A) 8.5 C) 12.8 @
2 no = 1~7BZ ‘.,\: 0‘ 15 22) 2The probability that a radish seed will germinate is 0.7. A gardener plants seeds' 1n batches of 15. Find the standard deviatio to: number of seeds germinating in each batch.
A) 9.9 C) 3.2 D) 31.5
its (0.1)(o.3\ 2' I .77166 D) 0.162 18) “C: _ .._.__. 5') : ,8‘10625- I
20) Q 21) D 22) B Determine if the outcome is unusual. Consider as unusual any result that differs from the mean by more than 2 standard deviations That' is, unusual values are either less than 11— 20 or greater than 1.1 + 20. g
23) According to AccuData Media Researckgﬁof televisions within the Chicago city limits are 23)
tuned to "Eyewitness News" at 5:00 pm on Sunday nights. At 5:00 pm on a given Sunday, 2500
such teievisions are randomly selected and checked to determine what' is being watched. Would it be unusual to find that 919 a - - . 00 televisions are tuned to "Eyewitness News"?
“2) Yes w C) 42 D) Purple M “19,00 uémcel Use the 213011160 Cl] Distribution to ﬁnd the indicated probability. C.
24) A mountain search and rescue team receives a mean of 0.78 calls per day. Find the probability that 24) on a randomly selected day, they will receive fewer than two calls.
A) 0.1840 B) 0.1394 C) 0.8160 D) 0.3576 25) m 25) The number of calls received by a car towing service averages 19. 2 per day (per 24— hour period).
-‘ ﬁter—finding—themean numberefeallsperu hour, f—i—nd—tlae—probabilit-yihata'na randomly-selected_____m7. hour the number of calls is 2
A) 0.17973 B) 0.11503 C) 0.15816 D) 0.14379 _ M 1': [El-1:1 ~_—_ 0% PoiSSOAPAlC(0165/1\ ...

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- Fall '11
- PatriciaToohey
- Statistics