What you provided works just fine. Suppose that you have these data:

5.9 20
6.4 24
7 28
9 36
9.9 40
10.1 44
10.8 48
12.7 60
13.4 72
14.7 84
15.2 96
15.8 120
5.9 25
6.4 29
7 33
9 41
9.9 45
10.1 49
10.8 53


in columns A, B and C, and in rows 1 through 19. Begin by selecting the
range A1:C19. Choose Insert | Chart, or click the Chart Wizard button
on Excel's main toolbar. In Step 1 of the Chart Wizard, choose
XY(Scatter) Chart, and click Next. In Step 2 of the Chart Wizard, you
should see two tabs, one labeled "Data Range" and one labeled "Series."


Click the "Series" tab. You'll see a listbox labeled "Series" and it
will have Series1 and Series2 in it. There are another two boxes on
that tab, one that is labeled X Values and one labeled Y Values. Both
Series1 and Series2 should have as their X values the range $A$1:A$19.
Series1 should have $B$1:B$19 as its Y values, and Series2 should have
$C$1:C$19 as its Y values. Click Finish, and I think you'll have the
chart that you're looking for.

C^2
Conrad Carlberg