Organising and dss steps in designing a spreadsheet solution


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Organising and dss steps in designing a spreadsheet solution

  1. 1. Steps in designing a spreadsheet solution <ul><li>Analysis </li></ul><ul><li>Design the solution </li></ul><ul><li>Implement the solution and test it </li></ul><ul><li>Refinement and Maintenance </li></ul>Task Example
  2. 2. Analysis <ul><li>Attempt to identify and understand the problem </li></ul><ul><li>How will the numbers get into the spreadsheet? Will the user type them into the appropriate cells or should a dialog box be used? </li></ul><ul><li>How should the output be displayed? </li></ul><ul><li>How many decimal places should be displayed in the answer? How should the numbers be formatted for display? </li></ul>N.B. Never make assumptions! Ask as many questions as are needed to completely understand what the client wants!!! Steps
  3. 3. Design the solution <ul><li>Draw a pen and paper model of the spreadsheet </li></ul><ul><li>Identify your sources of data </li></ul><ul><li>Plan the user interface </li></ul><ul><li>Develop the formulae that you will use </li></ul><ul><li>Test your design solution </li></ul><ul><li>Keep the client updated by showing your plans. </li></ul>Steps
  4. 4. Implement the solution <ul><li>Build the spreadsheet </li></ul><ul><li>Test the spreadsheet (working prototype) </li></ul><ul><ul><li>N.B. It is important to test every aspect of the spreadsheet, e.g. if you are using the IF function or LOOKUP function, all possible combinations should be tested. </li></ul></ul><ul><li>Show the working spreadsheet (prototype) to the client for feedback. </li></ul><ul><ul><li>Demonstrate it by using some of the test data you created. </li></ul></ul>Steps
  5. 5. Refinement and Maintenance <ul><li>REFINEMENT </li></ul><ul><li>Improvements may be requested. </li></ul><ul><li>External factors (e.g. changes to Tax system, like GST). </li></ul>After the client agrees with the solution, there may still be work to do: <ul><li>MAINTENANCE </li></ul><ul><li>Well designed spreadsheets and constructed are usually easy to maintain. </li></ul><ul><li>Time and effort invested up front is beneficial as changes may be difficult and costly to make </li></ul>Steps
  6. 6. Modelling a pricing system for a school disco <ul><li>TASK </li></ul><ul><li>You’re on a committee given the responsibility of organising the next school disco </li></ul><ul><li>There will be certain expenses </li></ul><ul><li>Money can be made from sales of tickets, drinks & chips </li></ul><ul><li>Work out how much to charge for these things so that a reasonable profit is made </li></ul><ul><li>Analysis </li></ul><ul><li>Designing the Solution </li></ul><ul><li>Implementing the solution </li></ul><ul><li>Refinement & Maintenance </li></ul>
  7. 7. Task Analysis <ul><li>ANALYSIS 1 - Pricing </li></ul><ul><li>Determine the prices for: </li></ul><ul><li>Tickets </li></ul><ul><li>Drinks </li></ul><ul><li>Chips </li></ul><ul><li>Problem: </li></ul><ul><li>Work out how to make $1000 profit to put towards equipment for the music department </li></ul><ul><li>If the prices are wrong: </li></ul><ul><li>Won’t make enough money for the music equipment </li></ul><ul><li>Make too much money, in which case the students (who you represent) will have paid too much! </li></ul><ul><li>ANALYSIS 2 - Questions </li></ul><ul><li>Spreadsheets are well suited to this task. Consider the following questions: </li></ul><ul><li>What data will be input into the system? </li></ul><ul><li>What calculations should be performed? </li></ul><ul><li>What form should the output take? </li></ul><ul><li>ANALYSIS 3 - Model (Input/Output) </li></ul><ul><li>The model should allow changes to the input to be reflected in the output: </li></ul><ul><ul><li>INPUTS </li></ul></ul><ul><li>Cost of the disco equipment </li></ul><ul><li>Cost of hiring the hall </li></ul><ul><li>Cost of advertising and printing tickets </li></ul><ul><li>Purchase prices of the drinks and chips </li></ul><ul><li>The total number of tickets, drinks & chips sold </li></ul><ul><li>Prices that will be charged for tickets, drinks & chips. </li></ul>Task Example
  8. 8. Task Design <ul><li>Construct a Pen & Paper model before attempting the electronic solution </li></ul><ul><li>Create a draft electronic spreadsheet from the P&P design </li></ul><ul><li>Develop the formulae for the figures that need to be calculated by the spreadsheet </li></ul><ul><li>Lock Formulae </li></ul><ul><li>Experiment and test </li></ul>Task Example
  9. 9. Task Implementation <ul><li>Once we’re happy with the design, it is time to build the spreadsheet </li></ul><ul><li>Verify the solution using all sets of test data </li></ul><ul><li>Compare it to the output expected </li></ul><ul><li>MORE TESTING </li></ul><ul><li>What if fewer students attend than originally thought? </li></ul><ul><li>What would happen to the figures </li></ul><ul><li>The expenses stay the same </li></ul><ul><li>To maintain profits, the selling prices would have to rise </li></ul>Task Example
  10. 10. Task Refinement & Maintenance <ul><li>As you build the spreadsheet, ask yourself how the model could be improved </li></ul><ul><li>Are there other inputs that could be considered or other results calculated? </li></ul><ul><li>You might consider displaying the results graphically </li></ul><ul><li>Finally, remember to document any changes you make </li></ul>Task Example
  11. 11. Bibliography <ul><li>Title: </li></ul><ul><li>Information Processes and Technology (HSC Course) </li></ul><ul><li>Authors: </li></ul><ul><li>Peter Ware, Paul Cheleski & Bill Chivers </li></ul><ul><li>Published by: </li></ul><ul><li>Jacaranda ( </li></ul>