$($b$)$ If in $($a$)$ you concluded that at least one mean is different from the others, determine which mean is different. The three sample means are

${\stackrel{}{x}}_1=24\mathrm{.}8,{\stackrel{}{x}}_2=23\mathrm{.}4,$ and ${\stackrel{}{x}}_3=27\mathrm{.}4$

Use Fisher's LSD procedure and let $=\mathrm{.}05.$