ANSWER
[tex]82.7[/tex]EXPLANATION
From the given data;
The total number of students is;
[tex]\begin{gathered} \sum_^f=1+4+7+2+8 \\ =22 \end{gathered}[/tex]Summation of the number of students and frequency;
[tex]\begin{gathered} \sum_^fx=(70\times1)+(75\times4)+(80\times7)+(85\times2)+(90\times8) \\ =70+300+560+170+720 \\ =1820 \end{gathered}[/tex]Recall that mean is calculated using;
[tex]\begin{gathered} x=\frac{\sum_fx}{\sum_^f} \\ =\frac{1820}{22} \\ =82.7272 \\ \cong82.7 \end{gathered}[/tex]Therefore the mean is 82.7
