A few comments which I think may help. The first one is that your expression
delta x = .12
should be
deltax = .12
I.e. no space between the delta
and the x
. (I realize that this is not used in your notebook to the point you showed, but you would probably use it in the next step.)
The second one is that your data1 parameter is a list that contains a list with the data you are interested in. I.e. it has the form
{
{number, number, number....}
}
And you want to interpolate, not data1
, but First[data1]
. (The reason it is a list inside of a list is that when Importing form Excel, each sheet in the original spreadsheet it placed in a separate list so you can access each sheet as needed for a multiple sheet spreadsheet.)
Thus your integration expression should be
Integrate[
Interpolation[First[data1], InterpolationOrder -> 2][x],
{x, 1, 256}]
Note that I also changed the integration range. Remember in Mathematica that array indices start at 1, not 0. If you take a look at the interpolation expression's output by evaluating the following on its own
Interpolation[First[data1], InterpolationOrder -> 2]
you will see the assumed range of the interpolation in the formatted output.
So your integration ultimately will be,
deltax (Integrate[
Interpolation[First[data1], InterpolationOrder -> 2][x],
{x, 1, 256}])
I hope this helps...