How do you call it when you remove the top n% and the bottom n% of a dataset? I am currently writing about a dataset of collected handwritings. I want to show some characteristics of the dataset. For example I think it is interesting to show how long it took users to create the dataset.
So I extract for each recording the time and thus get a list of non-negative real numbers. As a few instances have values > 30,000 and some < 5, but most instances are in [30, 60], I want to cut off those outliers and visualize only the rest in a plot.
So I remove the top 0.5% and the bottom 0.5% before visualizing it (where the x-axis is the time $t$ and the y-axis is the number of recordings with recording time lower than $t$).
Is there a name for removing the lower 0.5% and the top 0.5% of all datasets? (where 0.5% refers to the total number of datasets, not to the values)

When I have done this in the past,
this was called "trimming"
(not my term).
I used this to make graphics more visible,
and I typically trimmed
the top and bottom 5% of values,
not 5% of number of points.
More specifically,
if the values ranged from
0 to 100,
I removed all the points
with values
that were > 95
or < 5,
and then rescaled the display
so the remaining points
were displayed from the
min to the max
(usually 0 to 255).
I found that this made
details in the data much easier to see.
Another method is to
generate a histogram of the values
and adjust the displayed values
such that the modified display
has a uniform histogram.
This essentially uses
the inverse distribution.
