5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Mar 2010 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 27/05/2010   
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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 $24,030m and the calculated standard error in this case is $629m. The standard error is then used to interpret the level estimate of $24,030m.

For instance, the standard error of $629m indicates that:

  • There are approximately two chances in three that the real value falls within the range $23,401m to $24,659m ($24,030m ± $629m)
  • There are approximately 19 chances in 20 that the real value falls within the ranges $22,772m to $25,288m ($24,030m ± $1,364m)

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 March Quarter 2010 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
38
34
60
Manufacturing
25
105
116
Electricity, Gas, Water and Waste Services
4
18
18
Construction
24
276
283
Wholesale Trade
4
126
127
Retail Trade
50
88
101
Transport, Postal and Warehousing
23
86
90
Information Media and Telecommunications
7
29
31
Financial and Insurance Services
14
81
85
Rental, Hiring and Real Estate Services
311
360
515
Professional, Scientific and Technical Services
8
83
85
Other Selected Services
103
106
147
Total
331
509
629
New South Wales
171
251
316
Victoria
289
384
500
Queensland
162
114
196
South Australia
11
114
116
Western Australia
52
155
158
Tasmania
4
12
13
Northern Territory
9
63
63
Australian Capital Territory
5
4
6
Australia
331
509
629



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 $29,853m and the next quarter the published level estimate is $24,030m. In this example the calculated standard error for the movement estimate is $746m. The standard error is then used to interpret the published movement estimate of $5,823m.

For instance, the standard error of $746m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range $5,077m to $6,569m ($5,823m ±$746m)
  • There are approximately nineteen chances in twenty that the real movement falls within the range $4,331m to $7,315m ($5,823m ± $1,492m).

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

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
40
89
92
Manufacturing
39
186
193
Electricity, Gas, Water and Waste Services
5
27
28
Construction
30
303
308
Wholesale Trade
49
144
154
Retail Trade
55
115
124
Transport, Postal and Warehousing
23
202
199
Information Media and Telecommunications
7
24
27
Financial and Insurance Services
22
102
107
Rental, Hiring and Real Estate Services
454
267
539
Professional, Scientific and Technical Services
41
103
114
Other Selected Services
117
144
181
Total
488
516
746
New South Wales
146
341
372
Victoria
281
295
377
Queensland
187
165
254
South Australia
38
85
92
Western Australia
208
190
268
Tasmania
3
36
36
Northern Territory
8
49
50
Australian Capital Territory
207
52
212
Australia
488
516
746