Averages feel safe. One number, one answer. But a single average can hide almost everything that matters, and plenty of bad decisions have been made on one.
Check 1: mean or median?
Imagine a small company with ten staff. Nine earn ₦150,000 a month and the owner takes ₦1,950,000. The mean (the usual "average") is ₦330,000, more than double what nine of the ten people actually earn. The median, the middle value, is ₦150,000, which describes a typical employee. When a few extreme values exist, the median is usually more honest.
Check 2: what is the denominator?
"Sales grew 50%" could mean from 2 to 3 or from 2,000 to 3,000. Always ask: percent of what? A percentage without its base can make small things sound huge.
Check 3: how many people were counted?
Four out of five customers loved it sounds impressive until you learn that only five were asked. Small samples swing wildly, so confidence should grow with the number of observations.
Before you trust a number, ask these three questions. They take seconds, and they separate analysis from decoration.
Data Analysis: Turn messy data into answers people can act on.
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