Answer: remains unchanged.
- A increases by 5
- B increases by 25
- C remains unchanged
- D increases by 10
Correct answer: C. remains unchanged
Explanation: Adding a constant shifts the data without changing spread, so the variance is unchanged.
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