5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Mar 2011 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 26/05/2011   
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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 $26,046m and the calculated standard error in this case is $571m. The standard error is then used to interpret the level estimate of $26,046m.

For instance, the standard error of $571m indicates that:

  • There are approximately two chances in three that the real value falls within the range $25,475m to $26,617m ($26,046m $571m)
  • There are approximately 19 chances in 20 that the real value falls within the range $24,904m to $27,188m ($26,046m $1,142m)

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 2011 estimates.

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

Mining
57
58
90
Manufacturing
35
81
92
Electricity, Gas, Water and Waste Services
2
21
22
Construction
10
244
245
Wholesale Trade
4
59
60
Retail Trade
25
57
65
Transport, Postal and Warehousing
8
161
162
Information Media and Telecommunications
6
9
11
Financial and Insurance Services
5
19
20
Rental, Hiring and Real Estate Services
486
147
500
Professional, Scientific and Technical Services
96
61
111
Other Selected Services
100
112
169
Total
496
403
571
New South Wales
90
228
243
Victoria
265
192
349
Queensland
442
121
455
South Australia
9
63
65
Western Australia
55
168
177
Tasmania
7
27
34
Northern Territory
84
26
88
Australian Capital Territory
3
20
19
Australia
496
403
571




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 $31,349m and the next quarter the published level estimate is $26,046m. In this example the calculated standard error for the movement estimate is $730m. The standard error is then used to interpret the published movement estimate of -$5,303m.

For instance, the standard error of $730m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range -$6,033m to -$4,573 (-$5,303m $730m)
  • There are approximately nineteen chances in twenty that the real movement falls within the range -$6,763m to -$3,843m (-$5,303m $1,460m)

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

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

Mining
34
58
80
Manufacturing
47
151
163
Electricity, Gas, Water and Waste Services
12
19
20
Construction
8
321
319
Wholesale Trade
17
60
65
Retail Trade
47
95
100
Transport, Postal and Warehousing
103
211
250
Information Media and Telecommunications
7
39
39
Financial and Insurance Services
10
68
67
Rental, Hiring and Real Estate Services
273
263
369
Professional, Scientific and Technical Services
177
92
201
Other Selected Services
87
174
192
Total
362
593
730
New South Wales
177
310
388
Victoria
267
341
444
Queensland
57
199
212
South Australia
13
118
119
Western Australia
79
180
198
Tasmania
9
35
40
Northern Territory
88
37
81
Australian Capital Territory
22
24
33
Australia
362
593
730