Multiply each number of students to their respective number of books and then add the products.
[tex]4(2)+9(3)+13(4)=8+27+52=87[/tex]
Determine the total number of students by adding the number of students.
[tex]4+9+13=26[/tex]
Divide the obtained sum of the products by the total number of students.
[tex]\bar{x}=\frac{87}{26}\approx3.346\approx3.3[/tex]
