5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Sep 2010 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 25/11/2010   
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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 $26,362m and the calculated standard error in this case is $787m. The standard error is then used to interpret the level estimate of $26,362m.

For instance, the standard error of $787m indicates that:

  • There are approximately two chances in three that the correct value falls within the range $25,575m to $27,149m ($26,362m ± $787m)
  • There are approximately 19 chances in 20 that the correct value falls within the ranges $24,788m to $27,936m ($26,362m ± $1,574m)

The correct 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 2010 estimates.

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
43
54
70
Manufacturing
11
115
117
Electricity, Gas, Water and Waste Services
114
10
113
Construction
14
173
174
Wholesale Trade
25
62
65
Retail Trade
100
58
122
Transport, Postal and Warehousing
45
91
100
Information Media and Telecommunications
-
47
47
Financial and Insurance Services
7
59
59
Rental, Hiring and Real Estate Services
458
472
674
Professional, Scientific and Technical Services
74
113
151
Other Selected Services
94
117
156
Total
490
577
787
New South Wales
212
355
433
Victoria
62
380
378
Queensland
438
135
448
South Australia
71
120
128
Western Australia
119
125
162
Tasmania
1
13
14
Northern Territory
9
24
28
Australian Capital Territory
1
12
12
Australia
490
577
787
- 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 $27,991m and the next quarter the published level estimate is $26,362m. In this example the calculated standard error for the movement estimate is $606m. The standard error is then used to interpret the published movement estimate of $-1,629m.

For instance, the standard error of $606m indicates that:
  • There are approximately two chances in three that the correct movement over the two quarter period falls within the range -$2,235m to -$1,023m (-$1,629m ±$606m)
  • There are approximately nineteen chances in twenty that the correct movement falls within the range $2,841m to -$417m (-$1,629m ± $1,212m).

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

Buildings and Structures
Equipment, Plant and Machinery
Total
$m
$m
$m
Mining
25
135
142
Manufacturing
16
143
145
Electricity, Gas, Water and Waste Services
68
27
75
Construction
16
261
258
Wholesale Trade
26
73
75
Retail Trade
101
102
149
Transport, Postal and Warehousing
31
115
118
Information Media and Telecommunications
-
28
28
Financial and Insurance Services
6
55
55
Rental, Hiring and Real Estate Services
426
161
413
Professional, Scientific and Technical Services
37
96
104
Other Selected Services
145
176
253
Total
457
466
606
New South Wales
228
244
329
Victoria
175
213
279
Queensland
312
276
308
South Australia
34
76
86
Western Australia
88
132
169
Tasmania
4
14
15
Northern Territory
11
39
35
Australian Capital Territory
3
13
13
Australia
457
466
606
- nil or rounded to zero (including null cells)