5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Sep 2012 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 29/11/2012   
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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 $41,047m and the calculated standard error in this case is $513m. The standard error is then used to interpret the level estimate of $41,047m.

For instance, the standard error of $513m indicates that:

  • There are approximately two chances in three that the real value falls within the range $40,534m to $41,560m (41,047m ± $513m)
  • There are approximately 19 chances in 20 that the real value falls within the range $40,021m to $42,073m (41,047m ± $1,026m)

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 2012 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
400
137
406
Manufacturing
15
74
78
Electricity, Gas, Water and Waste Services
20
4
21
Construction
55
158
168
Wholesale Trade
22
46
51
Retail Trade
39
28
53
Transport, Postal and Warehousing
96
70
127
Information Media and Telecommunications
3
19
19
Financial and Insurance Services
9
27
28
Rental, Hiring and Real Estate Services
205
121
273
Professional, Scientific and Technical Services
42
102
109
Other Selected Services
97
93
152
Total
449
282
513
New South Wales
184
180
313
Victoria
116
84
135
Queensland
423
144
441
South Australia
83
33
90
Western Australia
105
145
174
Tasmania
3
40
40
Northern Territory
5
14
16
Australian Capital Territory
2
20
20
Australia
449
282
513



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 $43,637m and the next quarter the published level estimate is $41,047m.

In this example the calculated standard error for the movement estimate is $374m. The standard error is then used to interpret the published movement estimate of -$2,590m.

For instance, the standard error of $374m indicates that:
  • There are approximately two chances in three that the real movement over the two quarter period falls within the range -$2,964m to -$2,216m (-$2,590m ± $374m).
  • There are approximately nineteen chances in twenty that the real movement falls within the range -$3,338m to -$1,842m (-$2,590m ± $748m)

The following table shows the standard errors for September Quarter 2012 movement estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
51
116
130
Manufacturing
33
65
74
Electricity, Gas, Water and Waste Services
22
10
25
Construction
44
189
194
Wholesale Trade
26
56
58
Retail Trade
14
37
40
Transport, Postal and Warehousing
61
102
122
Information Media and Telecommunications
9
24
25
Financial and Insurance Services
24
34
45
Rental, Hiring and Real Estate Services
221
92
254
Professional, Scientific and Technical Services
44
149
153
Other Selected Services
98
105
154
Total
268
309
374
New South Wales
108
147
191
Victoria
138
121
189
Queensland
169
168
239
South Australia
72
72
112
Western Australia
63
170
192
Tasmania
3
50
50
Northern Territory
29
18
35
Australian Capital Territory
2
27
28
Australia
268
309
374