Summary statistics for a quantitative variable involve calculating measures of center like the mean and median, and measures of spread such as the range, interquartile range (IQR), and standard deviation.
The cognitive trap here is thinking these values are interchangeable.
They are not.
The mean is sensitive to extreme values, while the median is resistant.
Use the mean for symmetric distributions without outliers; use the median when outliers are present.
For spread, the range gives a quick sense of the data's span but is also affected by outliers; the IQR is more robust in such cases.
Standard deviation tells you how much data typically deviates from the mean but requires the assumption of normality for meaningful interpretation.
Choosing the wrong measure leads to incorrect conclusions about the data's variability or central tendency.
Don't just calculate; understand what each measure reveals about the dataset's shape and potential anomalies.