Q.The ages (in years) of 6 employees in a small office are: 28, 34, 25, 40, 31, 36. Find the mean age.

This is a set of 6 individual observations; the mean is the total of the ages divided by 6.

$28+34+25+40+31+36 = 194$

$\bar{x} = \dfrac{194}{6} \approx 32.33$

With $n=6$ individual observations, $\bar{x} = \dfrac{\sum x}{n}$.

Step 1 — Add the ages. Sorting first for a cleaner check: $25, 28, 31, 34, 36, 40$. Adding: $25+28=53$, $53+31=84$, $84+34=118$, $118+36=154$, $154+40=194$. So $\sum x = 194$.

Step 2 — Divide by 6.

Independent check. Adding the original (unsorted) list directly: $28+34=62$, $62+25=87$, $87+40=127$, $127+31=158$, $158+36=194$ — the same total, confirming the sum.

Miscounting the number of employees (using 5 or 7 instead of 6) is the usual slip in a short list like this — always recount the data points before dividing, and keep the exact fraction (194/6) before rounding the final answer.