Answer:
1.5
Step-by-step explanation:
Attached to this answer is the diagram of the box plot described in the question, and the means from the plot are calculated thus;
Students; no. of siblings
student 0 2
student 1 4
student 2 7
student 3 5
student 4 2
Total 20
Mean no. of siblings = (total number of siblings) ÷ (total number of students)
Note that number of students here are the once that had at least one sibling, others without siblings are not used in the calculation, hence 5 students (student-0 to student-4) make up total number of students, while the remaining 4 students (student-4 to student-9) are disregarded.
Therefore, mean = 20 ÷ 5 = 4 siblings.