5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Sep 2009 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 26/11/2009   
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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 $25,038m and the calculated standard error in this case is $751m. The standard error is then used to interpret the level estimate of $25,038m.

For instance, the standard error of $751m indicates that:

  • There are approximately two chances in three that the real value falls within the range $24,287m to $25,789m ($25,038m $751m)
  • There are approximately 19 chances in 20 that the real value falls within the ranges $23,536m to $26,540m ($25,038m $1,502m)

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 2009 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m

Mining
193
45
216
Manufacturing
29
85
89
Electricity, Gas, Water and Waste Services
27
39
50
Construction
16
172
171
Wholesale Trade
24
71
88
Retail Trade
22
91
96
Transport, Postal and Warehousing
46
256
265
Information Media and Telecommunications
12
37
43
Financial and Insurance Services
8
16
20
Rental, Hiring and Real Estate Services
85
504
516
Professional, Scientific and Technical Services
36
106
115
Other Selected Services
117
135
209
Total
261
692
751
New South Wales
115
337
336
Victoria
68
269
289
Queensland
199
200
295
South Australia
35
70
70
Western Australia
82
282
325
Tasmania
1
20
20
Northern Territory
na
na
21
Australian Capital Territory
na
na
60
Australia
261
692
751

na not available



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 $30,338m and the next quarter the published level estimate is $25,038m. In this example the calculated standard error for the movement estimate is $718m. The standard error is then used to interpret the published movement estimate of -$5,300m.

For instance, the standard error of $718m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range -$6,018m to -$4,582m (-$5,300m $718m)
  • There are approximately nineteen chances in twenty that the real movement falls within the range -$6,736m to -$3,864m (-$5,300m $1,436m).

The following table shows the standard errors for September Quarter 2009 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
mill.
mill.
mill.

Mining
168
72
193
Manufacturing
20
135
134
Electricity, Gas, Water and Waste Services
19
37
41
Construction
25
218
221
Wholesale Trade
19
92
101
Retail Trade
19
121
119
Transport, Postal and Warehousing
116
263
292
Information Media and Telecommunications
15
35
46
Financial and Insurance Services
5
26
25
Rental, Hiring and Real Estate Services
124
329
351
Professional, Scientific and Technical Services
39
132
144
Other Selected Services
185
201
294
Total
278
613
718
New South Wales
113
300
350
Victoria
143
254
311
Queensland
173
267
334
South Australia
25
86
88
Western Australia
135
269
315
Tasmania
1
68
68
Northern Territory
na
na
40
Australian Capital Territory
na
na
86
Australia
278
613
718

na not available