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: $\frac{71+82+88+ 92+ 93+ 97+99}{7}=88.857$.
The median is the the middle item in the sequence $71,82,88, 92, 93, 97,99$, which is: $92$.
There is no mode because all items appear the same number of times.
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: $99-71=28$, and the standard deviation is: $\sqrt{\frac{(71-88.857)^2+(82-88.857)^2+...+(99-88.857)^2}{7}}\approx8.967$
