To solve for the Lower Class Boundary, we will subtract 1/2 or 0.5 from the lower class limit from the given table:
[tex]\begin{gathered} 21-0.5=20.5 \\ 17-0.5=16.5 \\ 13-0.5=12.5 \\ 9-0.5=8.5 \\ 5-0.5=4.5 \\ 1=0.5=0.5 \end{gathered}[/tex]
If we put this to the table, we will have:
Now, to get the Cumulative frequency, we will add the frequency in each row. With this, we will have:
[tex]\begin{gathered} 5 \\ 5+8=13 \\ 13+18=31 \\ 31+24=55 \\ 55+11=66 \\ 66+4=70 \end{gathered}[/tex]
Adding this to the table and we will have: