The Following Information Regarding the Top Eight Fortune 500 Companies

The following information regarding the top eight Fortune 500 companies was presented in an issue of Fortune Magazine.
$\begin{array}{lrrr}&\text { Sales } & \text { Sales } & \text { Protits } & \text { Profits } \\\text { Company }&\$ \text { Millions } & \text { Rank } & \$ \text { Millions } & \text { Rank }\\\text { General Motors } & 161,315 & 1 & 2,956&30 \\\text { Ford Motor } & 144,416 & 2 & 22,071&2 \\\text { Wal-Mat Stores } & 139,208 & 3 & 4,430&14 \\\text { Exzon } & 100,697 & 4 & 6,370&5 \\\text { General Electric } & 100,469 & 5 & 9,269 &3\\\text { Int1 Business Machines } & 81,667 & 6 & 6,328 &6\\\text { Citigroup } & 76,431 & 7 & 5,807 &\\\text { Philip Morris } & 57,813 & 8 & 5,372&9 \\\text { Boeing } & 56,154 & 9 & 1,120&82 \\\text { AT\&T } & 53,588 & 10 & 6.398&4\end{array}$
a. How many elements are in the above data set?
b. How many variables are in this data set?
c. How many observations are in this data set?
d. Which variables are categorical and which are quantitative variables?
e. What measurement scale is used for each variable?