5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Dec 2011 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 01/03/2012   
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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 $40,608m and the calculated standard error in this case is $688m. The standard error is then used to interpret the level estimate of $40,608m.

For instance, the standard error of $688m indicates that:

  • There are approximately two chances in three that the real value falls within the range $39,920m to $41,296m ($40,608m ± $688m)
  • There are approximately 19 chances in 20 that the real value falls within the range $39,232m to $41,984m ($40,608 ± $1,376m)

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 2011 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
304
207
493
Manufacturing
61
126
147
Electricity, Gas, Water and Waste Services
10
54
61
Construction
5
199
199
Wholesale Trade
61
77
112
Retail Trade
21
42
47
Transport, Postal and Warehousing
51
144
158
Information Media and Telecommunications
1
10
10
Financial and Insurance Services
23
38
50
Rental, Hiring and Real Estate Services
179
103
201
Professional, Scientific and Technical Services
96
117
158
Other Selected Services
72
104
135
Total
382
442
688
New South Wales
136
197
235
Victoria
92
141
167
Queensland
137
172
232
South Australia
13
93
94
Western Australia
330
257
556
Tasmania
3
44
44
Northern Territory
2
12
12
Australian Capital Territory
5
10
12
Australia
382
442
688



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 $35,683m and the next quarter the published level estimate is $40,608m.

In this example the calculated standard error for the movement estimate is $527m. The standard error is then used to interpret the published movement estimate of $4,925m.

For instance, the standard error of $527m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range $4,398m to $5,452m ($4,925m ± $527m).
  • There are approximately nineteen chances in twenty that the real movement falls within the range $3,871m to $5,979m ($4,925m ± $1054m)

The following table shows the standard errors for December Quarter 2011 movement estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
60
200
208
Manufacturing
63
117
139
Electricity, Gas, Water and Waste Services
6
38
41
Construction
15
199
197
Wholesale Trade
15
98
98
Retail Trade
7
50
50
Transport, Postal and Warehousing
33
138
141
Information Media and Telecommunications
1
20
20
Financial and Insurance Services
12
46
46
Rental, Hiring and Real Estate Services
278
105
313
Professional, Scientific and Technical Services
32
119
119
Other Selected Services
93
178
197
Total
314
457
527
New South Wales
119
264
273
Victoria
247
191
323
Queensland
125
184
224
South Australia
18
47
52
Western Australia
96
247
266
Tasmania
3
63
63
Northern Territory
3
12
12
Australian Capital Territory
2
17
16
Australia
314
457
527