Answer:
To find the mean number of boys and girls in the three classes, we need to calculate the total number of boys and girls in all three classes, then divide by the number of classes.
Let's denote:
- \( B_1, B_2, B_3 \) as the number of boys in classes 1, 2, and 3, respectively.
- \( G_1, G_2, G_3 \) as the number of girls in classes 1, 2, and 3, respectively.
Given the data, let's say:
- Class 1 has 20 boys and 15 girls.
- Class 2 has 18 boys and 20 girls.
- Class 3 has 15 boys and 17 girls.
Now, we calculate the total number of boys and girls in all three classes:
Total number of boys: \( 20 + 18 + 15 = 53 \)
Total number of girls: \( 15 + 20 + 17 = 52 \)
To find the mean (average), we divide the total number of boys and girls by the number of classes (which is 3 in this case).
Mean number of boys: \( \frac{53}{3} ≈ 17.67 \) (rounded to two decimal places)
Mean number of girls: \( \frac{52}{3} ≈ 17.33 \) (rounded to two decimal places)
So, the mean number of boys in the three classes is approximately 17.67, and the mean number of girls is approximately 17.33.
