Answer: Data is on ordinal scale or ranks, or non-linear relationship suspected.
- A Data is normally distributed with a known population variance value
- B Data is on ordinal scale or ranks, or non-linear relationship suspected
- C Data has roughly equal variance across the observed groups
- D Used mainly for large samples exceeding thirty observations
Correct answer: B. Data is on ordinal scale or ranks, or non-linear relationship suspected
Explanation: Spearman rank correlation: non-parametric. Used for ordinal data or when linear relationship assumption fails.
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