Hi there, I hope you have time to read this question and offer a suggestion or two.
My basic question is this: I have data in sets of three. I would like to combine the data from each set, perform a function (probably just taking the median and MAD), then re-assign these values to each of the original sets of data. As a bit of background, I have performed a microscopy screen and analyzed the images using software called CellProfiler. I have three 'control' images that I would like to combine and then compare parameters from each of my 'treatment' images to the combined control data. However, there are a couple of 'wrinkles' to my problem: Not all the data is actually in sets of three. If there are no objects in a particular field,CellProfiler does not output anything for that image. For example, I could have the following data set: ImageNumber Measurement 1 5 2 7 3 8 4 3 6 9 So in this example, I would like to combine images 1 to 3 in one set and 4 to 6 in another set (image 5 was empty). Here is another 'wrinkle': For each image, there are multiple measurements based on the number of objects in the field of view I have measured. So my data actually looks something like this ImageNumber Measurement 1 4 1 5 1 5 2 6 2 7 2 8 3 8 3 9 4 1 4 1 4 6 4 3 6 10 6 9 6 5 6 8 I have attached a .csv containing a portion of the actual data (in this example, images 1 through 3 are not present). Right now, I can split the data.frame based on the ImageNumber column and perform functions, but I can't come up with a way of combining the data in a way that might account for the absence of some of the images. Thanks for reading and any help and suggestions are much appreciated. JT
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