Answer
See below.
Work Step by Step
The mean of $n$ numbers is the sum of the numbers divided by $n$. The median of $n$ is the middle number of the numbers when they are in order (and the mean of the middle $2$ numbers if $n$ is even). The mode of $n$ numbers is the number or numbers that appear(s) most frequently.
Hence here the mean: $\frac{216+ 203+ 225+ 216+ 212+ 228+ 209 }{7}=215.571$
The median is the middle item in the sequence $ 203,209,212,216,216, 225, 228$, which is: $216$. The mode is $216$.
The range is the difference between the largest and the smallest data value. The standard deviation of $x_1,x_2,...,x_n$ is (where $\overline{x}$ is the mean of the data values): $\sqrt{\frac{(x_1-\overline{x})^2+(x_2-\overline{x})^2+...+(x_n-\overline{x})^2}{n}}$.
Hence here the range is: $228-203=25$ and the standard deviation is: $\sqrt{\frac{(216-215.571)^2+(203-215.571)^2+...+(209-215.571)^2}{7}}\approx8.086$
