Here are some data for five companies in the same industry:

$\backslash$table$[[,$Company Code$],[,$A$,$B$,$C$,$D$,$E$],[$EBIT$,22\mathrm{.}75,57\mathrm{.}75,180\mathrm{.}25,-10\mathrm{.}50,203\mathrm{.}75],[$Interest$,6\mathrm{.}50,16\mathrm{.}50,51\mathrm{.}50,3\mathrm{.}50,2\mathrm{.}50]]$

a$.$ Calculate a measure of times$-$interest$-$earned for the industry.

b$.$ Calculate a measure of times$-$interest$-$earned for each company.

c$.$ Calculate the average of the times$-$interest$-$earned ratios for the individual companies.

d$.$ Does changing the method of calculation make a significant difference to the end result?