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: $\frac{49+39+31+30+29+28+27+27+27+22+21+21}{12}=29.25$.
The median is the average of the middle two in the sequence $49, 39, 31, 30, 29, 28, 27, 27, 27, 22, 21, 21$, which is: $(27+28)/2=27.5$.
The median is $27$.
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: $49-21=28$ and the standard deviation is: $\sqrt{\frac{(49-29.25)^2+(39-29.25)^2+...+(21-29.25)^2}{12}}\approx7.944$
