[tex]s^2=\displaystyle\sum\frac{(x-\bar x)^2}{n-1}=\frac1{n-1}\sum(x^2-2x\bar x+{\bar x}^2)=\frac{\displaystyle\sum x^2-2\bar x\sum x+{\bar x}^2}{n-1}[/tex]
where [tex]\bar x=22[/tex] is the mean. Since
[tex]\sum x^2=2568[/tex]
[tex]\sum x=110[/tex]
you have variance
[tex]s^2=\dfrac{2568-2(22)(110)+22^2}{5-1}=37[/tex]
and so the standard deiviation is
[tex]s=\sqrt{37}\approx6.083[/tex]
