What is the **arithmetic mean** of the five numbers $6$, $4$, $7$, $10$, and $4$?

The mean of $n$ numbers is the sum divided by $n$. Sum: $6 + 4 + 7 + 10 + 4 = 31$. Mean: $\dfrac{31}{5} = 6.2$. - Trap B ($6.0$) is the **median** of these five numbers (after sorting: $4, 4, 6, 7, 10$, middle value is $6$) — useful for the next question, but not the mean. - Trap D ($7.5 = 30/4$) miscounts $n$ as 4 or drops a value.