5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Sep 2009
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 26/11/2009
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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 \$25,038m and the calculated standard error in this case is \$751m. The standard error is then used to interpret the level estimate of \$25,038m.

For instance, the standard error of \$751m indicates that:

• There are approximately two chances in three that the real value falls within the range \$24,287m to \$25,789m (\$25,038m ± \$751m)
• There are approximately 19 chances in 20 that the real value falls within the ranges \$23,536m to \$26,540m (\$25,038m ± \$1,502m)

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 2009 estimates.

 Buildings and Structures Equipment, Plant and Machinery Total \$m \$m \$m Mining 193 45 216 Manufacturing 29 85 89 Electricity, Gas, Water and Waste Services 27 39 50 Construction 16 172 171 Wholesale Trade 24 71 88 Retail Trade 22 91 96 Transport, Postal and Warehousing 46 256 265 Information Media and Telecommunications 12 37 43 Financial and Insurance Services 8 16 20 Rental, Hiring and Real Estate Services 85 504 516 Professional, Scientific and Technical Services 36 106 115 Other Selected Services 117 135 209 Total 261 692 751 New South Wales 115 337 336 Victoria 68 269 289 Queensland 199 200 295 South Australia 35 70 70 Western Australia 82 282 325 Tasmania 1 20 20 Northern Territory na na 21 Australian Capital Territory na na 60 Australia 261 692 751 na not available

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 \$30,338m and the next quarter the published level estimate is \$25,038m. In this example the calculated standard error for the movement estimate is \$718m. The standard error is then used to interpret the published movement estimate of -\$5,300m.

For instance, the standard error of \$718m indicates that:
• There are approximately two chances in three that the real movement over the two quarter period falls within the range -\$6,018m to -\$4,582m (-\$5,300m ±\$718m)
• There are approximately nineteen chances in twenty that the real movement falls within the range -\$6,736m to -\$3,864m (-\$5,300m ± \$1,436m).

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

 Buildings and Structures Equipment, Plant and Machinery Total mill. mill. mill. Mining 168 72 193 Manufacturing 20 135 134 Electricity, Gas, Water and Waste Services 19 37 41 Construction 25 218 221 Wholesale Trade 19 92 101 Retail Trade 19 121 119 Transport, Postal and Warehousing 116 263 292 Information Media and Telecommunications 15 35 46 Financial and Insurance Services 5 26 25 Rental, Hiring and Real Estate Services 124 329 351 Professional, Scientific and Technical Services 39 132 144 Other Selected Services 185 201 294 Total 278 613 718 New South Wales 113 300 350 Victoria 143 254 311 Queensland 173 267 334 South Australia 25 86 88 Western Australia 135 269 315 Tasmania 1 68 68 Northern Territory na na 40 Australian Capital Territory na na 86 Australia 278 613 718 na not available