Trendline Power Equation Computes Wrong Values

[rdshadden]

I have the following data in which a power trendline was created but putting the original x-valued into the trendline equation did not give back the original y-values.

0.006439, 180.0
0.006603, 184.1
0.006849, 187.6
0.00716, 190.0
0.007603, 192.4
0.008079, 194.4
0.008571, 196.2
0.009194, 197.9
0.009751, 199.3
0.01024, 200.6
0.01067, 201.3

The equation calculated is y=178.541053723*x^0.0487980829

Substituting 0.006439 gives 139.5766.

 

[pgc01]

Hi

How did you calculate the equation?

I got

y = 491.021124102814 * x^0.194268652057119

Ex.:

x= 0.006439 y(calculated): 184.2562742 y(real): 180

x= 0.008079 y(calculated): 192.5596818 y(real): 194.4

 

[rdshadden]

Hi

How did you calculate the equation?

I got

y = 491.021124102814 * x^0.194268652057119

Ex.:

x= 0.006439 y(calculated): 184.2562742 y(real): 180

x= 0.008079 y(calculated): 192.5596818 y(real): 194.4

The equation was provided by the Excel trendline tool.

 

[JGordon11]

You need to use an xy scatter chart not a line chart

 

[rdshadden]

You need to use an xy scatter chart not a line chart

View attachment 89464

I will give that a try. Thank you for the help!!!