Respuesta :
To find the mean score, you need to calculate the sum of the products of the number of students and their corresponding scores, then divide by the total number of students.
Let's calculate it step by step:
Multiply the number of students by their respective scores:
7
×
90
=
630
7×90=630
18
×
80
=
1440
18×80=1440
15
×
70
=
1050
15×70=1050
10
×
60
=
600
10×60=600
Add up these products:
630
+
1440
+
1050
+
600
=
3720
630+1440+1050+600=3720
Add up the total number of students:
7
+
18
+
15
+
10
=
50
7+18+15+10=50
Divide the sum of the products by the total number of students:
Mean score
=
3720
50
=
74.4
Mean score=
50
3720
=74.4
So, the mean score of the test is
74.4
Answer: 74.4
Explanation
The first thing to do is multiply each pair of values for each of the given rows. Spreadsheet software is recommended if your teacher allows you to use it.
- 7*90 = 630
- 18*80 = 1440
- 15*70 = 1050
- 10*60 = 600
Then add up those products to get 630+1440+1050+600 = 3720. This is the total score of all students combined.
Divide this total score over the total number of students (50, which is given in the instructions or note how 7+18+15+10 = 50)
So, 3720/50 = 74.4 is the mean score.
For more information and examples, search out "weighted mean".
