A. Zaeske
ECON 41
Homework 1: Answer Key (Corrected)
1A
: (c)
1B
: (c)
1C
: (a)
1D
: (d)
2
: (c)
3
: (d)
4
: (d)
5
: (b)
6A
: (d)
6B
: (c)
3.13
:
a)
mean=¯
x
=
1
n
∑
x
= 1128
.
92 thousand employees
Ordering the data in ascending order, the 25th and 26th values are 739 and 759. We average
them to obtain the median. So median =
739+759
2
= 749 thousand employees
b)
The mode is 1200, which occurs three times.
3.25
: Using the given formula and the hint, combined mean= ¯
x
=
10
*
95+8
*
104
10+8
= 99
3.28
: The mean ¯
x
=
1
n
∑
x
= $79
,
520, so
∑
x
=
n
¯
x
= 5
*
$79
,
520 = $397
,
600
3.39
: The standard deviation is zero when each value of the data set is the same. Let
n
= 4
and
X
=
{
5
,
5
,
5
,
5
}
.
∑
x
= 20,
∑
x
2
= 100,
s
2
=
1
3
(
100

1
4
(20)
2
)
2
= 0. So
s
= 0 as well.
3.46
: Range 236.751.6 = 185.1,
∑
x
= 1147
.
30,
∑
x
2
= 169226
.
29
Sample Values :
s
2
=
1
9
(
169226
.
29

1
10
(1147
.
30)
2
)
2
= 4177
.
4
s
= 64
.
63
Population Values :
σ
2
=
1
10
(
169226
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This note was uploaded on 04/01/2008 for the course ECON 41 taught by Professor Guggenberger during the Winter '07 term at UCLA.
 Winter '07
 Guggenberger

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