.

Spreadsheets for EconolT,licAnalysis 125

than doubling each distance. Thelinechart is really designed to plotyvalues for different

,categories,such as pricesfor modelsof cars or enrollmentsfor differentuniversities.

Drawing anxyplot with Excel is easiest if the table of data lists thexvalues before the

yvalues. This convention makes it easy for Excel to specify one set ofxvalues and several

sets ofyvalues. The block ofxyvalues is selected, and then the chart tool is selected. Then

the spreadsheet guides the user through the rest of the steps.

Graph the loan payment as a function of the number of payments for a possible auto loan. Let the

number of monthly payments vary between 36 and 60. The nominal annual interest rate is 12%,

and the amountborrowedis $18,000..

The spreadsheet table shown in Figure 4-2 is constructed first. CellsAS:B10 are selected, and
then the Chartwizard icon is selected. The first step is to select anxy (scatter)plot with smoothed

== == = ==- = 'II' = ;

-..- - ..- ---

.-'"I

I I

-- - - - - - --

A B C D E F

1 12% nominal annual interest rate

2 1% monthly interest r-ate

(^3) $18,000 amount borrowed
(^4) i

Monthly

(^5) Payments Payment
6 36 $597.86 = PMT($A$2,A6,-$A$3)
7 42 $526.96
8 48 $474.01
9 54 $433.02 ..
10 60 $400.40 I
11
12 $600.00
13
14 =CI)S
(^15) j:I.
(^16) :2>. $500.00 ---------------- ----------------------------
17 = 0
18 ::E
(^19) I ,
20 $400.0036^42485460

. 21 Number.of Payments
22