Question 8

Explanation

To find the combined average of all classes, we need to calculate the total score of all students and divide it by the total number of students.

Step 1: Calculating Total Scores for Each Class

Class IPA ($n_1 = 30$, $\bar{x}_1 = 6.5$):

Class IPS ($n_2 = 25$, $\bar{x}_2 = 7$):

Class Bahasa ($n_3 = 20$, $\bar{x}_3 = 8$):

Step 2: Calculating Combined Average

The total score of all classes is:

The total number of students in all classes is:

Thus, the combined average ($\bar{x}_{total}$) is:

So, the average score of all these class 12 students is $7.07$.