Using the information provided below, answer questions $1-9.$

INFORMATION

During the first quarter of $2023,$ fifty $(50)$ Bachelor of Commerce in Informatics graduates were recruted into the graduate internship programme of a prominent JSE$-$listed Technology company, anonymised as ABC Ltd Each graduate intem rotated through each of the $5$ departments of ABC Ltd and sat for five separate departmental assessments at the end of each of the rotations. The HR department captured the final consolidated marks of the $50$ graduates for potential employment offers at ABC.

The sample data below represents the final marks $($in $\%)$ obtained by $20$ randomly selected graduates who participated in the internship at ABC Ltd$.$

$\backslash$table$[[56,78,66,82,52,72,62,64,59,79],[74,61,53,64,45,68,77,84,96,88]]$

$(4$ Marks$)$

using the group frequency provided in question $2,$derermine the mean mark obtained by the sample of $20$ graduate interns