On the line plot, each point or star represents the number of dogs that has a particular weight. We can see that
1 dog has a weight of 1/8
2 dogs has a weight of 3/8
4 dogs has a weight of 1/2
3 dogs has a weight of 5/8
Thus, the total number of dogs that was weighed is
1 + 2 + 4 + 3
= 10
10 dogs were weighed