5625.0 - Private New Capital Expenditure and Expected Expenditure, Australia, Dec 2003
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 26/02/2004
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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

To illustrate, let us say that the published level estimate for total capital expenditure is \$10,500m and the calculated standard error in this case is \$173m. The standard error is then used to interpret the level estimate of \$10,500m. For instance, the standard error of \$173m indicates that:

• There are approximately two chances in three that the real value falls within the range \$10,327m to \$10,673m (\$10,500m ± \$173m)
• There are approximately 19 chances in 20 that the real value falls within the ranges \$10,154m and \$10,846m (\$10,500m ± \$346m)

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 quarterly level estimates. These standard errors are based on a smoothed average of capital expenditure estimates.

 Buildings and structures Equipment, plant and machinery Total \$m \$m \$m Mining 11 16 36 Manufacturing 16 51 62 Construction 7 35 40 Wholesale trade 5 57 65 Retail trade 7 22 34 Transport and storage 10 40 45 Finance and insurance 3 29 31 Property and business services 52 62 84 Other services 69 36 89 Total 90 124 173 New South Wales 17 77 92 Victoria 73 71 108 Queensland 10 35 44 South Australia 2 13 27 Western Australia 5 25 32 Tasmania 1 8 8 Northern Territory na na 2 Australian Capital Territory na na 6 Australia 90 124 173 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 \$10,500m, and the next quarter the published level estimate is \$11,100m. In this example the calculated standard error for the movement estimate is \$221m. The standard error is then used to interpret the published movement estimate of +\$600m.

For instance, the standard error of \$221m indicates that:

• There are approximately two chances in three that the real movement over the two quarter period falls within the range \$379m to \$821m (\$600m ±\$221m)
• There are approximately nineteen chances in twenty that the real movement falls within the range \$158m to \$1,042m (\$600m ± \$442m)

The following table shows the standard errors for national quarterly movement estimates. These standard errors are based on a smoothed average of capital expenditure estimates.

 Equipment, plant and machinery Total \$m \$m Mining 23 49 Manufacturing 64 78 Construction 48 55 Wholesale trade 51 66 Retail trade 25 45 Transport and storage 49 53 Finance insurance 40 32 Property and business services 84 114 Other services 46 119 Total 153 221 New South Wales 99 103 Victoria 114 117 Queensland 75 100 South Australia 84 84 Western Australia 87 91 Tasmania 21 21 Northern Territory na 33 Australian Capital Territory na 67 Australia 153 221 na not available