The widths of equal-width buckets are calculated by dividing the highest value by the number of buckets. While technically accurate, this method may not be intuitive to the user. Rounding up the calculation of the widths used in equal-width buckets may improve the usability of the buckets while making a small sacrifice in their accuracy.
The rounding up of bucket widths is based on calculating the maximum value and then rounding it up so that the last bucket covers the maximum value. For example, if you have a large range of numbers with the highest value = 3876.77, and want to split the values into 10 buckets, then the bucket size is calculated as 3876.77 / 10 = 387.677. If this is rounded up to 400, then the revised buckets would have the following values: 0–400, 401–800, 801–1200, ..., 3201–3600, and 3601–4000. These new buckets would then be reflected in the distribution report as shown in the following figure.
For data with a small range of values where the highest value = 3.15, split into 10 buckets, bucket width is calculated as 3.15 / 10 = 0.31, rounded to 0.40. The revised buckets are then split into these values: 0–0.40, 0.41–0.60, 0.61–1.0, ..., 3.21–3.6, and 3.61–4.00 as reflected in the following distribution report.
