Transcript GraphingwithExcel

Graphing with Excel
The Basics
Working With Excel
• The spreadsheet program Excel is useful
for constructing data tables and graphs
• The results can easily be inserted into a
Word document of Power Point
presentation
• This presentation will introduce you to the
basics of data presentation with Excel
Working With Excel
• Consider the following example:
– One of the most important skills to learn in
driving is how to stop safely. No car can “stop
on a dime.” The faster the car is moving, the
further it travels before it stops. There is also
the “reaction time;” the time between the
decision to stop and the time the driver steps
on the brakes. During the reaction time, the
drive travels a certain distance, called the
“reaction distance.”
Working With Excel
• Using Excel, we will prepare a table and a
graph of original speed, reaction distance,
braking distance and total distance to
stop.
• Begin by opening Excel and inserting the
table headings (don’t forget the units)
Click and Drag here
To change cell size
Choose a cell and
type your text. Don’t forget
to add your units (like I did)
Note: Avoid entering
Any data in cell A1.
You can adjust font size and color as you
would in Word
Enter all your table headings and data
Two important things to remember here:
1. Enter independent variable (x-axis) first
2. Do not mix numbers and letters (text) in the data;
it will create a problem when you try to graph it
Click and drag to select
Right click to open
Select “Format Cells”
Select the “Number”
tab and choose the
appropriate category.
Here I will select
“number” and the
appropriate number
of decimal points
based on the precision
of my measurement.
This helps to keep
the correct number of
significant figures in
your data.
Take a moment to look at the other options in this menu
This will
allow you
to add
borders to
your data
table
Selecting the “Borders” option on the toolbar
Will open the “Draw Borders” feature
To make a graph, begin by highlighting the data you wish to
graph. Be sure to highlight only the numbers
Once the data is highlighted, select “Chart Wizard”
With Chart Wizard
open, select
“XY (Scatter)”
Then select Next
The next view
Should look
Like this
Note the three
Sets of data
Select Next
Here you can add a title to the graph and labels on the axes
Don’t forget to include units on your axes
Last step is to save your graph (or chart as it’s called)
Select Finish
A graph will now appear
In your spreadsheet.
You can drag, resize, and
copy-paste this just
like any image
used in Word
Let’s add a few more details before we finish
“Right Click” on any
one of the data points. The
points in that series will
be highlighted (as shown)
A box will open up.
Choose “Source Data”
Select “Series” tab
Here you can
Add names to
Your legend
(if you have one).
Select the series
Type name here
Select OK
“Right click” a data point
again to open menu box.
Select “Add Trendline”
Based on the
“shape”
of your data
points,
choose the
regression
type that best
fits.
For this
example, I am
selecting
linear, since
the data
points are
almost in a
straight
line
Select the
“Options” tab
Select “Display
Equation on
Chart”
This will give you the slope and equation for the
Best-fit curve through you data
The equation is in the form
y = mx+b
where m = slope and
b= y-intercept
Repeat for any additional
Data
Note: For the other plots, I selected the “power”
regression option since the data points
tended to curve instead of being in a straight line
Working With Excel
So what do these results mean?
Notice the reaction distance increases by
roughly the same amount for each
increase in speed (linear relationship). The
braking distance however, increases more
rapidly as the speed increases
(exponential relationship). In other words,
you need much more stopping distance for
a small increase in car speed.
Working With Excel
• From this point, you can save and print
your results right from Excel
• Alternately, your can copy-paste your table
and graph into your report if your are using
Word. This is a nice way to create a very
“finished” and professional–looking
document.