Solution for Homework 3
3.2 (a) The density curve forms a 1*1 square, which has area 1.
(b) 20%. The region is a rectangle with height 1 and base width 1 - 0.8 = 0.2.
(c) 60%. The region is a rectangl
General addition rule
For any two events A and B, p(A or
B) = p(A) + p(B) - p(A and B)
Conditional Probability
p(B/A) = p(A and B)
p(A)
General Multiplication Rule
For any two events A and B
p(A and B
Solutions of homework 10
t = 2.015.
(b) t = 2.518.
16.3 (a)
16.9 (a) df = 24.
(b) t = 1.12 is between 1.059 (p =0.15) and 1.318 (p = 0.10).
(c) Double the value of P because Ha is two-sided: The P-val
Solutions of homework 6
4.2 Water temperature is explanatory, and weight change (growth) is the responsive
variable. Both are quantitative.
4.6 (a) Graph is omitted. Speed is explanatory.
(b) The rela
Solutions of homework 9
14.2 (a) If
= 115, the distribution is approximately Normal with mean
= 115 and standard deviation /
25 = 6.
(b) The actual result lies out toward the high tail of the curve, w
Solutions of homework 8
10.19. In the long run, the gambler earns an average of 94.7 cents per bet. In other words, the
gambler loses (and the house gains) 5.3 cents for each $1 bet.
10.22. (a) Normal
Solutions of homework 7
5.30 Note that y = 46.6 + 0.41. We predict that Octavio will score 4.1 points above the
mean on the final exam: y = 46.6 + 0.41( x + 10) = 46.6 + 0.41 x + 1.4. (Alternatively,
Solution of homework 4
3.24
(a) About 5%: x < 240 corresponds to z < (240-266)/16 = 1.625. Table A gives
5.16% for 1.63 and 5.26% for 1.62.
(b) About 55%: 240 < x < 270 corresponds to (240-266)/16 < z
Solution of homework 5
10.24
(a) Let X be Shelias measured glucose level. P (X > 140) = P(Z > (140-125)/10) = P
(Z > 1.5) = 0.0668
(b) If x is the mean of four measurements (assumed to be independent)
Solution for Homework 11
Extra Problem Sheet:
9 (a) X = amount of cereal in the small bowl
Y= amount of cereal in the large bowl
T = X + Y (total amount)
E (T) = 4.0 and SD (T) = 0.5.
P (T > 4.5) = P
Solution for Homework 12
20.2 (a) The percentages, respectively, are 11/20 = 55%, 68/91 74.7%, and 3/8 =
37.5%.
(b) Some (but not too much) time spent in extracurricular activities seems to be
benefic
Math 171 Prelim #1 Solutions
1. (a) Let X be the monthly income of a randomly chosen male Cornell graduate. Let Y
be the monthly income of a randomly chosen female Cornell graduate. The total
monthly
LECTURE 1
Solution to homework one
Sec 4.2 problem 4,8
4: Use T for tails and H for heads.
(a): thesamplespacc is {(H,H,H) H H,T) (H,T, H), (H, T,T), (T, H, H) (T,H,T), (T, T, H), (T,T, T)}
D.
(T
Math 171 Final Exam (Spring 2004) Solutions
1. (a) Let X denote the players net winnings. Then, X = 7 3 or X = 0 3 with corresponding probabilities
P (X = 4) = 0.4 and P (X = 3) = 0.6.
Thus, by deniti
What does correlation mean?
Has no units
It is the strength of a linear
association between 2
quantitative variables
o
Remember:
r = zx z y
n 1
The correlation line goes through (0,0)
Has a slope of r