A sample of 50 students has a mean test score of 75. If 10 more students with an average of 90 join, what is the new mean?
✓ Correct Answer: Option A
Total original = 50 × 75 = 3750. New students = 10 × 90 = 900. New mean = 4650/60 = 77.5.
Total original = 50 × 75 = 3750. New students = 10 × 90 = 900. New mean = 4650/60 = 77.5.