| 1. Start
Excel. On some computers, there will be a shortcut
to Excel on the computer desktop and you can simply click
this icon. In other cases you will have to click
on START, move the pointer to the PROGRAMS menu, find EXCEL and click to start
the program. Once started, you will see the toolbar with the spreadsheet
below it. Picture
of the spreadsheet after this step.
2. Enter
your data. In the first column (column A) type your first X value and
press ENTER. The highlighted box should move from cell A1 (column A, row 1) to
A2 (column A, row 2). Type your second X value and press ENTER. Continue until
you have entered the complete set of X values. Move the cursor over cell B1 (column
B, row 1) and click. In the second column (column B) type your Y values. Picture
of the spreadsheet after this step.
3. Graph
you data. Place the cursor over cell A1 again
and click to highlight this cell. Now, hold down the
left mouse button and drag the cursor over the
entire data set (in this case, to cell B10), then release the cursor. The
data should appear inverted (white numbers on a black background)
to show they have
been selected.
Move
the cursor to the menu bar and choose CHART from the INSERT
menu. The chart wizard (designed to guide
you through the graphing process) should open. In
the
first step choose a XY (Scatter) graph type without connected dots. Picture
of the spreadsheet after this step. Press the next
button.
In the next panel, a preview of the graph will be shown. Click on the SERIES
tab and in the box labeled NAME, type a label for your data. In this case,
I wrote Zinc calibration data (Excel added the equal sign and quotation
marks).
Picture of the spreadsheet
after this step. Click the next button.
In the next panel you can customize the graph a little. At the very least,
you should add a X and Y axis title by clicking the TITLE tab. The titles
(including
units) should be entered in the VALUE (X) AXIS and VALUE (Y) AXIS spaces.
You can also change the chart title if you wish by typing in the CHART
TITLE box.
I will leave the auto-entered title. Picture
of the spreadsheet after this step. Click the next button.
In the
last panel, you get to place the graph next to your data
or on a separate "page" (worksheet).
Choose to add it as a separate page by clicking AS NEW SHEET. Click
the finish box. Your new graph will appear on the screen and a new
tab will
appear at
the bottom left corner of the screen labeled CHART 1. Close the chart
toolbar that
appears. You can select your data by clicking SHEET 1 and you graph
by clicking CHART 1. Picture of the spreadsheet after this step.
4. Print
your graph (optional). Choose PRINT from the FILE menu. In the dialog
box that appears, you will usually just click OK to print the graph. Sometimes
you may have to change the printer location or properties depending upon where
you are printing your graph. 5. Add a linear regression ("best fit")
curve if desired. While in the graph (chart 1) window,
choose ADD
TRENDLINE from the CHART menu.
Under
the TYPE tab, choose a linear curve. Picture
of the spreadsheet after this step.
Click on the OPTIONS tab and check the boxes to display the equation and the
R2 value. You can also enter a name for the fit (in this example, I wrote Linear
Fit), and choose to force the fit through the origin (if this is a valid data
point - usually you should not force the data through the origin). Picture
of the spreadsheet after this step. Click OK when done.
The linear curve
will appear on your graph, together with the equation and correlation
coefficient. In some cases, the number of digits
displayed for the intercept
(in this case, 2.9333) or slope (in this case, 0.7126) will be insufficient
for accurate calculations based on this graph. This happens
when very small numbers
are generated for slope or intercept.
In this example, we do have sufficient number of digits, but, if
we wanted to change this we can select the equation by clicking once
while the cursor is over
the equation. A box should appear around the text. Picture
of the spreadsheet after this step. Click the right mouse button while the cursor is over the box and select FORMAT
DATA LABELS from the short menu that appears. In the this dialog box, click on
the NUMBERS tab, select SCIENTIFIC numbers and change the NUMBER OF DECIMAL PLACES
to 3 or 4. By clicking on other tabs you can change other formatting parameters
for this label. Picture of the spreadsheet
after this step. Click OK when done.
The equation
for the fit will now be changed to scientific notation. You can
drag the equation around your graph by
holding down the left
mouse
button while
the cursor is over the equation and moving it. Release the mouse
button when you’re happy with the location. Add a title to
your graph (if you haven't done this already) by clicking on the
title area and
typing
(your title might
include your name, section number and date). Picture
of the spreadsheet after this step. 6. Print the graph as described above.
Based upon the
web site created by Simon
J. Garrett. |
