It's for actually creating a histogram. Basically the process of creating a histogram is
1) Create a bunch of bins
2) Count how many observations fall into each bin
3) Draw a histogram from that
The question the OP is asking is does it matter if when an observation falls on a bin edge (so maybe the first bin is 1.5-2.5 and the second is 2.5-3.5 and you have a data value of exactly 2.5) does it matter if you put it in the lower bin or the upper bin.
I asked the question because the shape of histograms differs depending on where you put this interval values. So, as per making decisions using descriptive statistics and a histogram, is this significant. Thanks in advance.
Is it you making the decisions? If so, just take it into account. If it is someone else just explain it to them and or perhaps refer to presentence in the area. I would imagine if you were smart enough to check it you can figure out the next step.
What will you be using the histogram for in particular?
It might be significant, but it probably is not. As Hlsmith said, you're smart enough to determine this.
Histograms are generally just used to get an idea of what kind of common distribution the data follows (e.g. normal, skewed). If the histogram is only a little off from a common distribution, then it shouldn't really matter if the histogram is left open or right open. It will still only be a little off.