7. For the following set of data find the mean, median, mode, and standard deviation.
(4 marks)
\[
\begin{array}{lllllllllllllllllllll}
2 & 8 & 11 & 0 & 13 & 1 & 5 & 4 & 6 & 3 & 7 & 12 & 4 & 11 & 5 & 18 & 9 & 2 & 10 & 7 & 4
\end{array}
\]

Step 1 ：First, find the mean by adding all the numbers and dividing by the total count of numbers: \(\frac{2+8+11+0+13+1+5+4+6+3+7+12+4+11+5+18+9+2+10+7+4}{21}\)

Step 2 ：Mean: \(\boxed{6.76}\)

Step 3 ：Next, find the median by sorting the numbers in ascending order and finding the middle value: \(0, 1, 2, 2, 3, 4, 4, 4, 5, 5, 6, 7, 7, 8, 9, 10, 11, 11, 12, 13, 18\)

Step 4 ：Median: \(\boxed{6}\)

Step 5 ：Then, find the mode by identifying the number that appears most frequently in the dataset: \(4\)

Step 6 ：Mode: \(\boxed{4}\)

Step 7 ：Finally, find the standard deviation by first calculating the variance (average of the squared differences from the mean) and then taking the square root of the variance: \(\sqrt{\frac{(2-6.76)^2+(8-6.76)^2+\cdots+(4-6.76)^2}{21}}\)

Step 8 ：Standard Deviation: \(\boxed{4.44}\)