Modelling

Modelling is the construction of a model by mathematical analysis and the testing of proposed models in known situations.

What does that mean?

Simply that we use maths to work out what will happen to data if we change certain parts of it.

For example if you are selling tea at 25p a cup and make a profit of £2.00 each day, what will happen to your profits if you raise the price to 30p?

We can model this using a spreadsheet and come up with a series of suggested answers.

Your task in the following lessons is to look at feeding animals in a zoo. You need to be able to perform “what if …” functions to decide upon the best way to feed your zoo animals.

On the next page there is a table showing how many of each animal you have and the cost of feeding them.

Load the Spreadsheet

Your teacher will show you how to load this spreadsheet; you need to calculate how much it costs to feed all the animals for a week.

Your budget is £1000; by how much did you underspend? Write your answers in the table.

Economic problems are forcing the zoo to cut costs; your budget is now only £500. You need to decide where to cut costs.

Do you cut the number of animals that you keep? Why have 10 lions?

Or

Do you decide to have fewer types of animals?

Are sea lions interesting enough to keep?

Make two suggestions for cutting down and change the numbers in the spreadsheet to suit. Write in the table the changes that you are going to make, then change the spreadsheet.

What is the balance? Model 1 £______Model 2 £______

How close to £500 can you get the cost and what did you have to do to achieve that result?

Write both Models of the cost of feeding your animals.

Animal / Cost per week to feed each animal / Number of animals / Total cost per week for animals
Lion / £25
Tiger / £30
Zebra / £5
Elephant / £20
Snake / £5
Penguin / £5
Sea lion / £20
Alligator / £5
Eagle / £1
Lion / £25
Total
Allowed / £500
Balance
Animal / Cost per week to feed each animal / Number of animals / Total cost per week for animals
Lion / £25
Tiger / £30
Zebra / £5
Elephant / £20
Snake / £5
Penguin / £5
Sea lion / £20
Alligator / £5
Eagle / £1
Lion / £25
Total
Allowed / £500
Balance

VOCABULARY LIST

There are a number of words that you should know, this vocabulary is listed below. When you hear each word you should put a tick in the box.

address / Cell / absolute cell reference
cell reference / Column / relative cell reference
Value / Cut
Variable / Data
Drag
Formula
Graph
Label
Model
Paste
Output / interrogate
Predict
Simulate
Template
Definition
A / Excel / This is the spreadsheet package on the school network consisting of a grid of cells which can contain text, numbers and formulae.
B / Icon / These are symbols displayed on a screen. The icons on a toolbar are used to do things like open or save a file.
C / Byte / The amount of space needed to store one character (a letter, a number or symbol).
D / Wrap / What happens to a line of text when you have too many words for one line and it flows onto the next line.
E / Keyboard / This is the most commonly used input device which allows the user to type in data to a computer.
F / CD / A storage device that can store about 650 MB (megabytes) of data. Often used to 'back up' files and store images (e.g. from a digital camera)
G / Model / What we do when we use a spreadsheet or other software to explore the effect of changing variables in a given scenario.
H / Software / The programs used on a computer.
I / Header / Information repeated at top of every page of a document
J / Mouse / This is an input device which has buttons which are used to make selections from a menu, highlight things and move things around the screen.
K / Cell / A place to put data in on a spreadsheet.
L / Graph / A way of representing data in picture form.
M / Variable / A number that can be changed.
N / Bit / The smallest unit of data. 8 bits make one byte.
O / Calculate / A spreadsheet does this automatically to work out your answers and keep them up to date.
P / Absolute / A link to a cell that never changes.
Q / Copy / To place information onto the clipboard.
R / Paste / To put information from the clipboard into a cell.
S / Formula / Rules for linking cells mathematically.
T / Predict / When we try to guess what will happen if we change a value in a cell.
U / Sheet / One page of a spreadsheet.
V / Function / A ready-made complicated formula.
W / Sort / To put in order alphabetically or numerically.
X / Hyperlink / An active link between two items often in a multimedia presentation such as web pages or a slideshow.
Y / Autosum / Adds up a block of numbers.
Z / Macro / A little program to do things when you click on a button or press a combination of keys.
A / B / C / D / E / F / G / H
Excel / Icon / Byte / Wrap / Keyboard / CD / Model / Software
I / J / K / L / M / N / O / P
Header / Mouse / Cell / Graph / Variable / Bit / Calculate / Absolute
Q / R / S / T / U / V / W / X
Copy / Paste / Formula / Predict / Sheet / Function / Sort / Hyperlink
Y / Z
Autosum / Macro

Spreadsheet Bingo

1)______2)______3)______

Computer games
/ Computer Assisted Design / Simulation
/ Mathematical model

Advantages
Disadvantages

Homework

Using the following list of advantages and disadvantages fill out the table above, you need to be able to decide which is the most sensible for each use of a computer.

A “fantasy football” model can generate results whatever the weather! / Powerful and expensive computers are needed to run CAD effectively. / It is cheaper to test things using a simulation. / Using a mathematical model is less risky as it can show the effects of decisions
Virtual reality allows us to visit places and do things we may not see or do in real life. / CAD software is very expensive to buy. / Tests can be repeated as many times as wanted with a simulation. / A mathematical model can be altered easily to show the effect of making changes
Flight simulators are a safer and cheaper way of learning to fly. / People need a lot of training to use CAD software. / Using a simulated test allows us to study dangerous events safely. / A mathematical model can calculate results much faster than a person could
Playing simulation games can be a fun way of learning. / CAD is hard to do properly. / A test simulation will help to predict when something will become unsafe. / A mathematical model is more reliable as it will not make mistakes with calculations
Computer games involving fighting may influence some people to behave violently. / Designs can be created quickly using a library of components in a CAD package. / A simulated test may give misleading results. / It is difficult to see if a mathematical model has errors in it
Driving in a race simulation may give people a false impression of their real driving ability. / It is easier and quicker to change a design made with a computer than one done manually. / It can take a very long time to build an effective test simulation. / The people who use a mathematical model may not understand how it works
The rules in a computer game usually can’t be changed in order to make it work differently. / Using a CAD package allows you to re-size and rotate your design automatically. / Expensive hardware and software may be needed for running a test simulation. / It may cost a lot of money to get someone to set up a mathematical model or to change it.
Computer games can be very addictive and may cause health problems such as eye strain. / It is cheaper to use a CAD package to try out different finishes for your design. / A test simulation is only as good as the rules it is based on. / The person who sets up a mathematical model needs to be very good at maths