Find the mode from the following table: 
Step 1: Identify the modal class.
The class with the highest frequency is \(30–40\), so it is the modal class.
Step 2: Write the given data.
\[ L = 30, \quad f_1 = 23, \quad f_0 = 21, \quad f_2 = 14, \quad h = 10 \] Step 3: Apply the formula for mode.
\[ \text{Mode} = L + \left(\dfrac{f_1 - f_0}{2f_1 - f_0 - f_2}\right) \times h \] Step 4: Substitute the values.
\[ \text{Mode} = 30 + \left(\dfrac{23 - 21}{2(23) - 21 - 14}\right) \times 10 \] \[ = 30 + \left(\dfrac{2}{46 - 35}\right) \times 10 = 30 + \dfrac{20}{11} = 31.82 \] Step 5: Conclusion.
Hence, the mode = 31.82 (approx.).
The coefficient of correlation of the above two data series will be equal to \(\underline{\hspace{1cm}}\)
\[\begin{array}{|c|c|} \hline X & Y \\ \hline -3 & 9 \\ -2 & 4 \\ -1 & 1 \\ 0 & 0 \\ 1 & 1 \\ 2 & 4 \\ 3 & 9 \\ \hline \end{array}\]
Identify the median class for the following grouped data:
\[\begin{array}{|c|c|} \hline \textbf{Class interval} & \textbf{Frequency} \\ \hline 5-10 & 5 \\ 10-15 & 15 \\ 15-20 & 22 \\ 20-25 & 25 \\ 25-30 & 10 \\ 30-35 & 3 \\ \hline \end{array}\]
Find the unknown frequency if 24 is the median of the following frequency distribution:
\[\begin{array}{|c|c|c|c|c|c|} \hline \text{Class-interval} & 0-10 & 10-20 & 20-30 & 30-40 & 40-50 \\ \hline \text{Frequency} & 5 & 25 & 25 & \text{$p$} & 7 \\ \hline \end{array}\]