Solutions to Chapter 2.
Chapter 2: # 2.3, 2.4, 2.7, 2.12, 2.15, 2.16, 2.17, 2.19, 2.20, 2.23, 2.26, 2.27, 2.30, 2.37
2.3
CPI percentage growth forecasts:
3.0, 3.1, 3.4, 3.4, 3.5, 3.6, 3.7, 3.7, 3.7, 3.9
a.
Compute the sample mean
35
3.5
10
i
x
x
n
b.
Compute the sample median = middlemost observation:
3.5
3.6
3.55
2
c.
Mode = most frequently occurring observation = 3.7
2.4
Department store % increase in dollar sales: 2.9, 3.1, 3.7, 4.3, 5.9, 6.8, 7.0, 7.3, 8.2, 10.2
a.
Mean
59.4
5.94
10
i
x
x
n
Median = middlemost observation:
5.9
6.8
6.35
2
c.
The distribution is relatively symmetric since the mean of 5.94 is relatively close to the median
of 6.35.
Since the mean is slightly less than the median, the distribution is slightly skewed to the left.
2.7
Find the measures of central tendency for the number of defects in a sample of 50 radios
Mean number of defects =
0(12) 1(15)
2(17)
3(6)
50
= 1.34 defects per radio
Median = 1 (middlemost observation in the ordered array), Mode = 2 (most frequently
occurring observation)
2.12
The variance and standard deviation are
143
.
5
7
36
1
)
(
2
2
n
x
x
s
i
and
s = 2.268
2.15
The time that a sample of employees took to complete a task
Variable
N
N*
Mean
SE Mean
TrMean
StDev
Variance
CoefVar
Minimum
Ex2.15
24
0
28.96
2.77
28.05
13.57
184.13
46.86
12.00