The heights (in $cm$) of $12$ students are as follows:
$159, 148, 138, 150, 165, 166, 145, 152, 155, 160, 147, 151$
Find the mean,the median,and the mode.

(N/A) $1$. Mean: The mean is the sum of all observations divided by the total number of observations.
Sum $= 159 + 148 + 138 + 150 + 165 + 166 + 145 + 152 + 155 + 160 + 147 + 151 = 1836$.
Mean $= 1836 / 12 = 153 \ cm$.
$2$. Median: First,arrange the data in ascending order:
$138, 145, 147, 148, 150, 151, 152, 155, 159, 160, 165, 166$.
Since the number of observations $(n = 12)$ is even,the median is the average of the $6^{th}$ and $7^{th}$ terms.
Median $= (151 + 152) / 2 = 303 / 2 = 151.5 \ cm$.
$3$. Mode: The mode is the value that appears most frequently. In this dataset,every value appears exactly once,so there is no mode.