5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Dec 2009 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 25/02/2010   
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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 $30,007m and the calculated standard error in this case is $719m. The standard error is then used to interpret the level estimate of $30,007m.

For instance, the standard error of $719m indicates that:

  • There are approximately two chances in three that the real value falls within the range $29,288m to $30,726m ($30,007m ± $719m)
  • There are approximately 19 chances in 20 that the real value falls within the ranges $28,569m to $31,445m ($30,007m ± $1,438m)

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 2009 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
45
69
89
Manufacturing
46
189
195
Electricity, Gas, Water and Waste Services
7
25
26
Construction
32
187
191
Wholesale Trade
47
116
128
Retail Trade
8
114
115
Transport, Postal and Warehousing
35
193
199
Information Media and Telecommunications
13
45
46
Financial and Insurance Services
24
68
75
Rental, Hiring and Real Estate Services
211
493
571
Professional, Scientific and Technical Services
48
108
132
Other Selected Services
141
141
208
Total
249
614
719
New South Wales
108
283
308
Victoria
65
524
533
Queensland
104
142
167
South Australia
43
79
92
Western Australia
203
168
276
Tasmania
-
34
34
Northern Territory
2
24
24
Australian Capital Territory
1
58
58
Australia
249
614
719
- 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 $24,651m and the next quarter the published level estimate is $30,007m. In this example the calculated standard error for the movement estimate is $682m. The standard error is then used to interpret the published movement estimate of $5,356m.

For instance, the standard error of $682m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range $4,674m to $6,038m ($5,356m ±$682m)
  • There are approximately nineteen chances in twenty that the real movement falls within the range $3,992m to $6,720m ($5,356m ± $1,364m).

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

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
44
60
83
Manufacturing
34
222
231
Electricity, Gas, Water and Waste Services
15
30
34
Construction
32
242
233
Wholesale Trade
50
85
104
Retail Trade
15
114
118
Transport, Postal and Warehousing
36
303
306
Information Media and Telecommunications
10
18
24
Financial and Insurance Services
19
71
78
Rental, Hiring and Real Estate Services
223
288
353
Professional, Scientific and Technical Services
17
123
124
Other Selected Services
113
183
227
Total
244
642
682
New South Wales
60
440
454
Victoria
88
332
361
Queensland
107
207
217
South Australia
50
105
121
Western Australia
204
304
389
Tasmania
1
34
34
Northern Territory
2
27
26
Australian Capital Territory
1
36
36
Australia
244
642
682