Answer: 9.
- A 6
- B 7
- C 8
- D 9
Correct answer: D. 9
Explanation: Range = maximum - minimum = 11 - 2 = 9.
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