how to de-spike the values on this graph?

Hi cat3appr,

If this were my data, I'd reduce the number of points that are displayed on the graph by about a factor of 100. Physically, the data does not seem to be normally distributed, as the spikes all appear to be on the 'low' side.
I would smooth the data as follows:
a. Take the next group of 100 data points
b. Remove the 'n' lowest data points from the group. I would start with n=5.
c. Take the average of the remaining data points, to be used for plotting.

Adjust the total number of data points in each sample, and the number of points removed, until you get satisfactory results.

See the following for a formula to implement a similar algorithm:
http://www.mrexcel.com/forum/excel-q...owest-2-a.html

You may need to use helper columns.

Lewis

Duplicate Question - see Duplicate - see http://www.excelforum.com/excel-form...ess-spiky.html