Typically a collection if they are organized. If not, they may be referred to as a collection or an accumulation.
Sheet
Because the data set is sometimes called a group
It is called a data set.
set
"A set" is a collective noun so it takes the singular: was It can be confusing eg "a set of stamps WAS stolen" BUT "some stamps WERE stolen"
This is called a set.
Because the data set is sometimes called a group
A smudge
Cluster
A solution set
a bunch of hot heads.
{| |- | The first step is to identify the stamps. Consult a stamp catalog such as Scott's, which include pictures and descriptions of all the stamps. They typically include a price for the set as well as the individual stamps. It also provides details on identification as well as a description on how stamps are rated and graded. |}
An assortment is a group of things which are different; a group of things which are the same is called a set.