t (min)0≤t<55≤t<1010≤t<2020≤t<50frequency18324030\begin{array}{c|rrrr}t\text{ (min)}&0\leq t<5&5\leq t<10&10\leq t<20&20\leq t<50\\\hline\text{frequency}&18&32&40&30\end{array}t (min)frequency0≤t<5185≤t<103210≤t<204020≤t<5030
Calculate the frequency densities and identify the modal class.
A student says the widest bar must contain the most observations. Explain the error.