Time-Series data

Suggested series in PC/INFOS SCHOOLS that display good seasonal fluctuations:

  • Electricity generation
  • Retail Trade by store type
  • Meat and dairy production
  • Exports of major commodities

PC/INFOS SCHOOLS has two methods for removing the seasonal fluctuations:

  • Using the sum option and selecting moving averages

Or

  • Using the smoothing option and selecting centered moving average.

For this task we are going to use the sum option.

At any time using PC/INFOS SCHOOLS, you can hit the F1 key (top row of keyboard) - this will take you straight into the HELP MENU.

Part 1: Sums - Moving Average

In this exercise we will take a series that has obvious seasonal fluctuations and perform a Moving Average function on that series. This function helps to even out the seasonal fluctuations so that it is easier to see trends in the data.

  • Select the series.

Expand topic 10 – Production and Distribution.

Expand ‘Retail Trade Survey’

Select Table 15500-05 ‘Retail Sales: Quarterly by Store Type: Actual:.

Select the series ‘Retail Sales: per head of population: Actual’.

  • Perform a Moving Average on the series.

Go to SERIES, SUMS, choose ‘Moving Average’, change the periods to 4 (to cover one year), and hit OK.

You will be prompted to copy the new series to a workfile. Choose OK. You will now be in the new workfile with the parent series and the new series, which contains the moving averages of the parent series.

  • Select the two series and view the data.

Go to VIEW, DATA or click on the icon on the tool bar.


To enable you to see its effect more clearly, escape out of the data table (hit the ‘Esc’ key) and go to VIEW, GRAPH or click on the icon on the tool bar.

  • Escape out of the graph. (hit the ‘Esc’ key).
  • Close the workfile.

FILE, CLOSE (do not save changes to the workfile).

  • Collapse all the levels.

VIEW, COLLAPSE

Index numbers

Suggested series in PC/INFOS SCHOOLS that are examples of index numbers

  • Consumers Price Index
  • Food Price index
  • Producers Price Index
  • Capital Goods Price Index
  • Farm Expenses Price Index
  • Labour Cost Index
  • Overseas trade Index

At any time using PC/INFOS SCHOOLS, you can hit the F1 key (top row of keyboard) - this will take you straight into the HELP MENU.

Part 1: Index numbers

In this exercise we will use the Index function to compare the average weekly earnings with the Consumers Price Index ie have wages kept up with inflation.

  • Select the series.

Expand topic 8 – Labour Market.

Expand ‘Quarterly Employment Survey’

Expand Table 5504-11F ‘Average Weekly Earnings - Persons

Select the series ‘Average Weekly Earnings [FTE]: Persons: Total All Sectors’.

Copy to a Workfile

Expand topic 6 - Prices

Expand ‘Consumers Price Index’

Expand Table 18501-01 – Consumers Price Index: Food and All Groups

Select CPI: New Zealand All Groups

Copy to your Workfile

  • Creating the index numbers for the Average Weekly Earnings

Go to WINDOWS, WORKFILE

Select the series ‘Average Weekly Earnings [FTE]: Persons: Total All Sectors’.


Go to SERIES, INDEX

You will be prompted to set the Base value, when it begins and the periods in the base. They need to be set to the same as the CPI.
Base Begins – June 99
Base value – 1000
Periods in base – 4

Click on options. Set the decimal to zero and click OK

Click OK on the Index Dialog Box. A new series will appear in the list.


Select the new series and hold down the CTRL key and select the ‘CPI New Zealand: All Groups’ series and click on the Graph icon on the tool bar.

  • Escape out of the graph. (hit the ‘Esc’ key).
  • Close the workfile.

FILE, CLOSE (do not save changes to the workfile).

  • Collapse all the levels.

VIEW, COLLAPSE