5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Dec 2010 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 24/02/2011   
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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 $31,504m and the calculated standard error in this case is $731m. The standard error is then used to interpret the level estimate of $31,504m.

For instance, the standard error of $731m indicates that:

  • There are approximately two chances in three that the real value falls within the range $30,773m to $32,235m ($31,504m ± $731m)
  • There are approximately 19 chances in 20 that the real value falls within the ranges $30,042m to $32,966m ($31,504m ± $1,462m)

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 December Quarter 2010 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
90
55
117
Manufacturing
48
160
175
Electricity, Gas, Water and Waste Services
327
10
327
Construction
108
209
261
Wholesale Trade
16
52
60
Retail Trade
61
67
100
Transport, Postal and Warehousing
27
207
210
Information Media and Telecommunications
9
35
36
Financial and Insurance Services
8
66
66
Rental, Hiring and Real Estate Services
438
311
494
Professional, Scientific and Technical Services
134
98
173
Other Selected Services
114
154
201
Total
522
509
731
New South Wales
200
275
358
Victoria
342
301
468
Queensland
435
198
446
South Australia
13
143
146
Western Australia
80
139
169
Tasmania
7
26
28
Northern Territory
63
39
80
Australian Capital Territory
22
18
26
Australia
522
509
731



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 $26,680m and the next quarter the published level estimate is $31,504m. In this example the calculated standard error for the movement estimate is $835m. The standard error is then used to interpret the published movement estimate of $4,824m.

For instance, the standard error of $835m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range $3,989m to $5,659m ($4,824m ±$835m)
  • There are approximately nineteen chances in twenty that the real movement falls within the range $3,154m to $6,494m ($4,824m ± $1,670m).

The following table shows the standard errors for December Quarter 2010 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
42
69
87
Manufacturing
45
114
115
Electricity, Gas, Water and Waste Services
344
8
344
Construction
108
253
300
Wholesale Trade
29
69
77
Retail Trade
81
96
95
Transport, Postal and Warehousing
26
207
209
Information Media and Telecommunications
6
24
25
Financial and Insurance Services
10
25
27
Rental, Hiring and Real Estate Services
179
386
428
Professional, Scientific and Technical Services
98
100
135
Other Selected Services
98
172
204
Total
461
606
835
New South Wales
269
397
521
Victoria
359
302
485
Queensland
59
254
271
South Australia
71
151
154
Western Australia
108
109
146
Tasmania
7
25
29
Northern Territory
63
41
74
Australian Capital Territory
21
11
25
Australia
461
606
835