**Unformatted text preview: **9-10. (Twenty points) Grant wants to know What the correlation is between hours of exercise per week and feeling good (1-100)
[Assume it is safe to treat feeling good has an interval settle] Please help Grant and calculate the correlation coeﬂicient for these two
variables. The standard deviation of hours of exercise is 4.00 and the standard deviation of feeling good is 12.00 [These were calculated
using N not N-l, and it is recommended that you use N not N—1.] You must show all your work Exercise Feelin Good Cx-§>(y-?> (X _§X\1’ 4"?) 2€x_ )ZDZLKIQ =7 ’77
62 *5 ”1‘6 5* 60v =177/5 : 33+ -_ 7
1 4 - 71 _ .. 5-
”}: We E ‘2 1? - 35% -ﬂ -
11 89 3 :5 '15 r " 3,7575
, ‘1le H8 1 1-12. (twenty points) Using the correlation you got in the above answer (and continuing to use the data): Amy exercises 15 hours perweek. What is her estimated level of feeling good? -— -— \
- __ S l5 5 #5 r: r E: 22,25 a“ Y [DX ?30 .2.le (J
b 0:}‘6x i737b7‘ '1' 1 g 57'%—7S A
- ﬂ: @ﬁd' Y=€7.87S-+Z,Z|ZSX
b~ 5x2 . la -z,2125 57375,,2‘2‘2505) :17“?ng 13. As speciﬁcally as possible, state when it is appropriate to divide by n—l when calculating the variance. (,9ng Vou A26 affaﬂmagﬂpér i’OFUum-lou
YWMMﬁ ()51L36f WPLZ' W pawn 14. What is the probability of having any of the bottom three cards of a deck of eards be a heart?
.I / , - -
WSW/>- Frau/18nd} leases/5a) 15. Let’s say a household is prosperous if its income exceeds $75,000. Let’s say a household is educated if the householder completed
college. Select an American household at random, and let A be the event that the selected household is prosperous and let B be the event
that it is educated. According to the census bureau, P(A) = 0.12, P(B) = 0.30, and the probability that it is prosperous given that it is
educated [i.e., the probability of A given B] equals 0.20. What is the probability that it is educated given that it is 13W ,‘llrlint:
This question isn’t a difﬁth as it sounds, but it is deﬁnitely a “two-step” question. Figure out one other probability ﬁne-and than solve
this question] You must show work. :L 17. What is rolling a die 720 times and getting between either more than 135 sixes or less than 101 sixes? You must show work. (39-120 ’0?“ I01~Izo :«m '_m L5- 18. Traditionally, I give one free question on a ﬁnal. 'iﬁis is it. Here are ten points.- You need not answer this question to get points,
but if you wish to you may. Where is the center of California? Where do you think it is? Where do you think it should be? How do you deﬁne a point as the center of a state?
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- Fall '10
- RajendraM.Patel