STA103 HW9 Solution
Jilei Yang
May 31, 2015
12.4
Solution:
prob-value = Pr(X 20, 200) = Pr
X
20, 200 21, 000
/ n
2000/ 16
= Pr(Z 1.6) = .0548.
Since prob-value> .05, we cannot reject H0 in favor of H1 at .05 level.
12.6
Solution:
We have X = 535.57, s

STA103 HW8 Solution
Jilei Yang
May 17, 2015
11.2
Solution:
Here = 4, n = 15, X = 3.
(a) The 95% condence interval:
4
X z.025 = 3 1.96 = 3 2.02 or (0.98, 5.02).
n
15
(b) The 90% condence interval:
4
X z.05 = 3 1.64 = 3 1.69 or (1.31, 4.69).
n
15
(c) The 95

STA103 HW2 Solution
Jilei Yang
April 5, 2015
5.2
Solution:
Lets denote head by H, tail by T .
(a) The sample space is cfw_(HHHH), (T HHH), (HT HH), (HHT H), (HHHT ), (T T HH), (T HT H),
(T HHT ), (HT T H), (HT HT ), (HHT T ), (HT T T ), (T HT T ), (T T HT

STA103 HW5 Solution
Jilei Yang
April 25, 2015
8.2
Solution:
Let H=Harvard, C=Columbia, N=NYU.
The 9 possible school combinations of these two students are listed in the table below. They are
1
equally likely, i.e., each school combination comes with proba

STA103 HW6 Solution
Jilei Yang
May 2, 2015
9.2
Solution:
(a) The random variable X is the number of a chip marked.
X could be 1, 2 or 3, with
Pr(X = 1) = .5, Pr(X = 2) = .3, Pr(X = 3) = .2,
i.e.,
p(1) = .5, p(2) = .3, p(3) = .2.
Thus,
E(X) =
Xp(X) = 1(.5)

Statistics 103, Spring 2015, Practice Midterm III Solution
Part One: Multiple Choice
(b) (1/1)X + (1/2)Y + (1/10)Z
(c) (1/3)X + (1/6)Y + (1/30)Z
1. True or false: A 95% condence interval for
based on a sample of size 10 is shorter than a
95% condence int

STA103 HW2 Solution
Jilei Yang
April 5, 2015
5.2
Solution:
Lets denote head by H, tail by T .
(a) The sample space is cfw_(HHHH), (T HHH), (HT HH), (HHT H), (HHHT ), (T T HH), (T HT H),
(T HHT ), (HT T H), (HT HT ), (HHT T ), (HT T T ), (T HT T ), (T T HT

STA103 HW3 Solution
Jilei Yang
April 11, 2015
6.3
Solution:
Let B = boy, G = girl.
sample space
BBB
BBG
BGB
GBB
BGG
GBG
GGB
GGG
X = # girls
0
1
1
1
2
2
2
3
Since the outcomes in the sample space are equally likely, we know
X
0
1
2
3
+1
3
8
+2
3
8
+3
X 2 p

Statistics 103, Spring 2015, Practice Midterm I Solution
Instructions:
5. In a random sample of four individuals, their weight
is recorded as follows (in pound):
The exam is 50 minutes, closed book, and closed
notes.
112, 154, 135, 107
There are several

Homework 5: Chapter 8 of Caniglia
Problems from Chapter 8 of Caniglia: 8.2, 8.8, 8.10, 8.15, 8.16, 8.19, 8.23, 8.24,
8.26, 8. 27, 8.28, 8.30, 8.34, 8.37, 8.38, 8.39.
Extra Problem 1. In professional football, the team that gets the ball rst in overtime
is

Statistics 103, Spring 2015, Practice Final
Instructions:
5. Let X denote the number of times a web server
is accessed within the rst minute of next Saturday. Suppose X can be modeled with the following probability mass function:
The exam is closed book