SetNull -9999 to NoData changes minimum value of output raster *positive* values

Discussion created by earoberts on Jan 10, 2012
Latest reply on Jan 11, 2012 by earoberts
All: I use SetNull (in Raster Calculator) to change -9999 values to NoData, but this process also changes the minimum value of my positive "real" data in the resulting raster. E.g., my input raster has 153.78 as a minimum value (after I have "excluded" -9999 in my Symbology/Classification dialog), but after I execute SetNull("mm95_2011_normals.tif"   == -9999 ,"mm95_2011_normals.tif") the output raster has a minimum value of 162.38. I cannot find the missing / changed cells anywhere. This has happened in multiple rasters. The Spatial Analysis Histogram tool returns the same min/max values as the display classification.

Is it possible that the exclusion of -9999 in Symbology is causing an artifact? Any ideas?   Thanks.