A Researcher Who Is Examining Stress-Related Hormones Has Data on Indivdiuals

Short Answer

A researcher who is examining stress-related hormones has data on indivdiuals' body mass index. Below are the data
$$\begin{array} { c c } \hline \text { BMI } & f \\\hline 18 & 4 \\19 & 11 \\20 & 6 \\21 & 24 \\22 & 39 \\23 & 33 \\24 & 35 \\25 & 39 \\26 & 41 \\27 & 36 \\28 & 22 \\29 & 16 \\30 & 19 \\\hline\end{array}$$ What is the most common body mass index in this sample?