Chapter 7
7 - 2
Solutions:
1.
a.
AB, AC, AD, AE, BC, BD, BE, CD, CE, DE
b.
With 10 samples, each has a 1/10 probability.
c.
E and C because 8 and 0 do not apply.; 5 identifies E; 7 does not apply; 5 is skipped since E is
already in the sample; 3 identifies C; 2 is not needed since the sample of size 2 is complete.
2.
Using the last 3-digits of each 5-digit grouping provides the random numbers:
601, 022, 448, 147, 229, 553, 147, 289, 209
Numbers greater than 350 do not apply and the 147 can only be used once.
Thus, the
simple random sample of four includes 22, 147, 229, and 289.
3.
459, 147, 385, 113, 340, 401, 215, 2, 33, 348
4.
a.
6, 8, 5, 4, 1
Nasdaq 100, Oracle, Microsoft, Lucent, Applied Materials
b.
!1
0
!
3
,
6
2
8
,
5
0
0
252
!(
)!
5!(10 5)!
(120)(120)
N
nN n
==
=
−−
5.
283, 610, 39, 254, 568, 353, 602, 421, 638, 164
6.
2782, 493, 825, 1807, 289
7.
108, 290, 201, 292, 322, 9, 244, 249, 226, 125, (continuing at the top of column 9) 147, and 113.
8.
13,
8,
23,
25,
18,
5
The second occurrences of random numbers 13 and 25 are ignored.
Maryland, Iowa, Florida State, Virginia, Pittsburgh, Oklahoma
9.
102, 115, 122, 290, 447, 351, 157, 498, 55, 165, 528, 25
10.
finite, infinite, infinite, infinite, finite
11. a.
xx
n
i
=
Σ
/
54
6
9
b.
s
n
i
=
−
−
Σ
()
2
1
Σ
i
−
2
=
(-4)
2
+ (-1)
2
+ 1
2
(-2)
2
+ 1
2
+ 5
2
=
48
s
=
48
61
31
−
=
.