Answer: 16.
- A 15
- B 16
- C 17
- D 14
Correct answer: B. 16
Explanation: Sum = 150. Remove 20, add 30: new sum = 160. New mean = 160/10 = 16.
In a perfectly normal (bell-shaped) distribution, mean, median, and mode all coincide at the centre; about 68% of data falls within 1 standard deviation of the mean, 95% within 2, and 99.7% within 3 - the empirical rule used to judge how typical or extreme a value is.
Concept context
Mean, median, mode, standard deviation, and data interpretation