5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Sep 2013 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 28/11/2013   
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APPENDIX SAMPLING ERRORS


LEVEL ESTIMATES


INTRODUCTION

The estimates in this publication are based on a sample drawn from units in the surveyed population. Because the entire population is not surveyed, the published estimates are subject to sampling error. The most common way of quantifying such sampling error is to calculate the standard error for the published estimate or statistic.


EXAMPLE OF USE

The following example illustrates how to use the standard error to interpret a level estimate.

Let us say that the published level estimate for total capital expenditure is $40,742m and the calculated standard error in this case is $411m. The standard error is then used to interpret the level estimate of $40,742m.

For instance, the standard error of $411m indicates that:

  • There are approximately two chances in three that the real value falls within the range $40,331m to $41,153m (40,742m ± $411m)
  • There are approximately 19 chances in 20 that the real value falls within the range $39,920m to $41,564m (40,742m ± $822m)

The real value in this case is the result we would obtain if we could enumerate the total population.

The following table shows the standard errors for September Quarter 2013 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
99
32
108
Manufacturing
28
79
96
Electricity, Gas, Water and Waste Services
41
20
51
Construction
9
161
160
Wholesale Trade
18
73
78
Retail Trade
53
77
97
Transport, Postal and Warehousing
78
132
154
Information Media and Telecommunications
1
21
21
Financial and Insurance Services
7
36
36
Rental, Hiring and Real Estate Services
199
100
213
Professional, Scientific and Technical Services
36
88
93
Other Selected Services
98
117
152
Total
249
315
411
New South Wales
83
157
195
Victoria
158
130
222
Queensland
127
192
226
South Australia
100
64
129
Western Australia
80
138
152
Tasmania
43
20
48
Northern Territory
1
6
6
Australian Capital Territory
-
16
16
Australia
249
315
411
- nil or rounded to zero (including null cells)



MOVEMENT ESTIMATES


EXAMPLE OF USE

The following example illustrates how to use the standard error to interpret a movement estimate.

Let us say that one quarter the published level estimate for total capital expenditure is $41,668m and the next quarter the published level estimate is $40,742m.

In this example the calculated standard error for the movement estimate is $514m. The standard error is then used to interpret the published movement estimate of -$926m.

For instance, the standard error of $514m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range -$1,440m to -$412m (-$926m ± $514m).
  • There are approximately 19 chances in 20 that the real movement falls within the range -$1,954m to $102m (-$926m ± $1,028m)

The following table shows the standard errors for September Quarter 2013 movement estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
102
112
161
Manufacturing
35
83
95
Electricity, Gas, Water and Waste Services
30
28
40
Construction
9
188
189
Wholesale Trade
27
66
76
Retail Trade
55
98
108
Transport, Postal and Warehousing
31
174
172
Information Media and Telecommunications
3
23
24
Financial and Insurance Services
28
25
34
Rental, Hiring and Real Estate Services
258
137
303
Professional, Scientific and Technical Services
47
72
87
Other Selected Services
95
124
179
Total
319
390
514
New South Wales
76
206
234
Victoria
176
147
242
Queensland
186
222
283
South Australia
91
65
107
Western Australia
63
168
174
Tasmania
47
37
61
Northern Territory
1
10
10
Australian Capital Territory
1
16
16
Australia
319
390
514