Trendline equation factor problem

  • Thread starter Thread starter Christoffersson
  • Start date Start date
C

Christoffersson

Gurus,

When creating a chart with the following specs;

Values(y): Category(x) axis labels:
10 20
20 25
30 30
40 35
50 40

I get a good looking chart. Now I wanna have excel make me a linea
trendline and I also wanna make excel give me the equation of th
trendline.

Excel the shows a correct trendline but the equation is of by a facto
10. In this case it says: y = 5x + 15 when it really should say y
0,5x + 15. It seems like it doesn't care about the x axis labels (i
it only a label then) but simply take the integer 1 between eac
label.

How would one make excel produce the correct equation in a case such a
this?

Thanks in advance, Christoffersso
 
Christoffersson -
... It seems like it doesn't care about the x axis labels (is it only a
Click to expand...
label then) but simply take the integer 1 between each label. How would one
make excel produce the correct equation in a case such as this? <

Use an XY (Scatter) chart type instead of the Line chart type.

- Mike Middleton, www.usfca.edu/~middleton
 
Change from a "Line" chart to an "XY (Scatter)" chart.

The "Line" chart has nothing to do with whether you want a line or not.
Instead, the "Line" chart is used when you have no arithmetic x-scale.
X-values do not need to be given with a "Line" chart, and are only
used as labels, not values if given. It would help avoid confusion if
there were no option to fit a trendline on a "Line" chart, since it has
no meaning in the absence of an arithmetic scale. Since the x-labels
are not considered to be arithmetic, the trend line is computed based on
assumed x-values of 1,2,3,... with a "Line" chart, even if (as in your
case) you have provided x-labels that could potentially be interpreted
arithmetically.

Also, you have reversed the column labels. The first column by default
(and also in your equations) is x, not y.

Jerry
 
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