$7.(12$ Points$)$ Top Broadcast Shows. The networks for the top $20$ television shows, as determined by the Nielsen Ratings for the week ending October $26,2008,$ are shown in the following table.

$\backslash$table$[[$CBS$,$ABC,CBS$,$ABC,ABC$],[$FOX$,$CBS$,$CBS$,$FOX,CBS$],[$ABC$,$CBS$,$CBS$,$CBS$,$FOX$],[$FOX$,$FOX,CBS$,$FOX,ABC$]]$

a$)$ Use single$-$value grouping to organize these data into the following frequency and relative frequency table.

$\backslash$table$[[\backslash$table$[[$Names of the$],[$networks$]],$Frequency,Relative Frequency$],[,,]]$

b$)$ Draw a relative$-$frequency histogram for the data based on the Table from part a$).$