DA0-002 Data Analysis Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  IQR

  Why this is correct

  The interquartile range is the difference between the third and first quartiles (Q3 minus Q1), so it spans exactly the middle 50% of ordered observations. Unlike range or standard deviation, it ignores extreme values, describing central spread precisely.

• ✗

  Range

  Why it's wrong here

  Range subtracts the minimum from the maximum, so it reflects only the two extreme values and ignores the middle 50% entirely. It suits quick full-spread checks on small datasets. The interquartile range measures spread between the 25th and 75th percentiles.

• ✗

  Standard deviation

  Why it's wrong here

  Standard deviation measures dispersion around the mean across the entire dataset, not the middle 50%. It suits symmetric interval data where mean deviation is meaningful. The interquartile range captures spread between the 25th and 75th percentiles, describing the middle half.

• ✗

  Variance

  Why it's wrong here

  Variance squares deviations from the mean across all observations, describing overall dispersion rather than the middle 50%. It suits statistical modelling and variance decomposition. The interquartile range spans the 25th to 75th percentiles, directly measuring middle-half spread.