Question

The mean of the dataset is 15. What numberis missing?18, 16, ____, 9, 12, 23​

Answer 1

Answer:

12

Step-by-step explanation:

The Mean is the average of the numbers: a calculated "central" value of a set of numbers.

To calculate it:

• add up all the numbers,

• then divide by how many numbers there are.

$mean=\dfrac{a_1+a_2+a_3+...+a_n}{n}$

We have: 18, 16, x, 9, 12, 23 - six numbers (n = 6) and mean = 15.

Substitute:

$\dfrac{18+16+x+9+12+23}{6}=15\\\\\dfrac{78+x}{6}=15\qquad\text{multiply both sides by 6}\\\\6\!\!\!\!\diagup\cdot\dfrac{78+x}{6\!\!\!\!\diagup}=(6)(15)\\\\78+x=90\qquad\text{subtract 78 from both sides}\\\\78-78+x=90-78\\\\x=12$