2, 3, 4, 5, 5, 5, 6, 7, 8

IQR = Q3 - Q1

Find the Median (Q2) first,
2, 3, 4, 5, 5, 5, 6, 7, 8

Now, find Q1 and Q3 by again finding the median on left and right side of Median (Q2),
2, 3 / 4, 5, 5, 5, 6 / 7, 8
Q1 = \(\frac{3+4}{2} = 3.5\) and Q3 = \(\frac{6+7}{2} = 6.5\)

So, IQR = 6.5 - 3.5 = 3

Now, Standard Deviation is given by\(\sqrt{\frac{Σ(x_n - μ)^2}{n}}\)
Where,
μ = Mean
\(x_n\) = numbers in given data

μ = \(\frac{45}{9} = 5\)

\((x_n - μ)\) values: (2 - 5), (3 - 5), (4 - 5), (5 - 5), (5 - 5), (5 - 5), (6 - 5), (7 - 5), (8 - 5) = -3, -2, -1, 0, 0, 0, 1, 2, 3

\((x_n - μ)^2\) values: 9, 4, 1, 0, 0, 0, 1, 4, 9

\(Σ(x_n - μ)^2\) values: 9 + 4 + 1 + 0 + 0 + 0 + 1 + 4 + 9 = 28

So, SD = \(\sqrt{\frac{28}{9}} = 1.763\)