How you present your data matters a lot.
I have complete agreement on that matter. Axis without labels or mismatched colors haunt me at night, because you forgot what chart shows next week already.
I only disagree about previous statement that graph is too small, which is not true, I always spend extra effort and storage space to generate higher resolution images.
MaxFristerYour assumptions are correct. Dark lines are result of gaussian_filter1d from python lib over data, just to see a data trend.
All calculations, like median, min/max, sdev are done on raw unfiltered data, trend used only for graph purposes.
Bottom graph is traditional seconds timescale, imagine just as oscilloscope, but with very slow time/division. I have posted Python plotter generator app sourcecode few posts back, when we went thru bitseeker's dataset.
Top graph is relation between temperature (ambient sensor on X axis) and measurand (Y axis). This graph is not very clear, because temperature change was too little.
Usually better data have temperature swing >5c (e.g. AC on / AC off cycle).
Perhaps
rhb could log FX with large temperature swing (e.g. one day AC on, one day AC off) if he is interested in temperature stability of his 34401A.
Because measured FX reference have TC <0.05ppm/K, it's own error usually only a tiny fraction of the 34401A's own TC error.