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**Unformatted text preview: **Quiz 113 Stat 251 Name \— MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Solve the problem. 1) A local eat-in pizza restaurant wants to investigate the possibility of starting to deliver pizzas. The 1) ﬂ
“0“ M 3% owner of the store has determined that home delivery will be successful if the average time spent “41 M >3<p on the deliveries does not exceed 36 minutes. The owner has randomly selected 15 customers and
‘ m Us has delivered pizzas to their homes in order to test if the mean delivery time actually exceeds 36
n minutes. Suppose the p—value for the test was found to be .0272. State the correct conclusion. @t a = .025, we fail to reject H0. ~—B—)At a = .05, we fail to reject H0. ‘ ‘
-€)*At a = .02, we reject H0. -B)~At a = .03, we fail to reject H0. -016
2) Private colleges and universities rely on money contributed by individuals and corporations for 2) .
i: m their operating expenses. Much of this money is put into a fund called an endowment, and the
I college spends only the interest earned by the fund. A recent survey of eight private colleges in the
S? United States revealed the following endowments (in millions of dollars): 60.2, 47.0, 235.1, 490.0,
C1; ~. 0 A b 122.6, 177.5, 95.4, and 220.0. Summary statistics yield 3: = 180.975 and s = 143.042. Calculate a 90%
(7‘ ._ O \O confidence interval for the mean endowment of all private colleges in the United States.
f . ‘5 i . S. 4 = lam/116121.949 1+ .047a>—. .4151:
an _ 005 1‘00 017 1604 1/7‘. (13,6... 1gb 46.1)86‘25
’74)
3%: 7 A) 180.975 : 94.066 ‘ 13) 180.975 : 102.453
t n ‘ jam 9 C) 180.975 t 100.561 @ 180.975 I 95.836 {3‘ b3 egg/D \ 3) Let to be a specific values of t. Find to such that the following statement is true: d+¢ ‘4 1(12t()):.lwheredf:gg SHORT ANSWER. ' ' 4) A consumer product magazine recently ran a story concerning the increasing price of
VCR‘s. The story stated that VCR prices dipped in the early 1990's but now are beginning
“05M 1 to skyrocket in price. According to the story, the price of a VCR in 1992 was $209. A sample H4 >104 of 16 VCR's in 1998 yielded an average price of $279 and a standard deviation of $70.
0k __ O . DE Perform a hypothesis test to determine if the average price of VCR's in 1998 exceeds the (X _ 0 075 price in 1992. Use 0. = .05. Please show all work from null and alternative hypotheses to
/9' T ‘ interpretation of the result.
[ff/z .45 Y m t: 2.9% "2.04 = 35 Z
'— 9 +214 1 lo; "- =
A :2. EH «rel ‘15 Se 70
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\mutﬁcwm tvldcntc we the average? emcee mm m Wﬁb exccc'ds are Pym
m Wt; lo 8) The FDA wants to compare the mean caffeine contents of two other brands of 6—02. cola, Brand A )
and Brand B. independent random samples of 6—oz. cans of each brand were selected and the
caffeine content of each can determined. The study provided the following summary information. v —fP+——t’:s—
Bran A Bra Sample size 15 10
Mean (ounces) 18 20
Variance 1.2 1.5 Suppose the above interval is computed to be (—7, 3) (not the true interval, but assume that it is).
Interpret this interval practically. ml 1’ mi?! \M We are 99% confident that the true mean caffeine content of Brand A, m, exceeds the true mean caffeine content of Brand B cola, v.2. @e are 99% confident that (3Z1 — ;2), the difference between the sample mean caffeine contents
of 6—07.. cans of Brand A and Brand B cola, is included in our interval. A l\ ’ lYTl‘f’YVA l—Q—We are 99% confident that the true mean caffeine content of Brand B cola, uz, exceeds the true mean caffeine content of Brand A, 11.1. mfﬂV/ll Qﬁased on the 99% confidence interval, there is no evidence of a difference between the true (,DYt‘l/l l V) S 0 mean caffeine content of Brand A, m, and the true mean caffeine content of Brand B cola, “2. 0
m6 ‘0 9) We are interested in determining whether men's and women's attitudes on the environment differ. 9) D
/ To do so we sampled 100 men and 100 women and asked: "Do you think the environment is a
n2: D major concern in the 1990's?" Of those sampled, 67 women and 53 men responded that they 6 , £59, : Babelieved it is. Suppose a 96.06% confidence interval really was (.02, .26). Based on this interval,
7‘ 1:0 what is the relationship between p1 and p2 (where p1 = proportion of women)? £17750 H’l WWith 96.06% confidence, p1 < p2./m “1:05 C l ' 0 i4 bow -B)-With 96.06% confidence, p1 = p2. muudeg O
Vwoﬂo ~—G)—We cannot tell from the information provided.
2 \/ lo @With 96.06% confidence, p1 > p2.
‘ ’ Q 4F D‘szltl) A bottling company needs to produce bottles that will hold 10 ounces of liquid for a local brewery. 10) C
Periodically, the company gets complaints that their bottles are not holding enough liquid. To test
“7 ()5 this claim, the bottling company randomly samples 25 bottles and finds the average amount of liquid held by the 25 bottles is 9.6 ounces with a standard deviation of .2 ounce. Calculate the
appropriate t distribution test statistic. My? 0 ~A—)—t—= —50.000 B) t = —9.798 @t = —10.000 D) t = —4.472
t’ X; = amp—it) ‘ _O.,+ 0 ~’)_
tam (72-?) M ll
t ...

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- Fall '06
- staff
- Normal Distribution, Student's t-distribution, mean caffeine contents