Which of the Following Represents the Difference in Two Population $\mu _ { 1 } - \mu _ { 2 }$

Multiple Choice

Which of the following represents the difference in two population proportions?

A) $\mu _ { 1 } - \mu _ { 2 }$
B) $p _ { 1 } + p _ { 2 }$
C) $\frac { \sigma 1 ^ { 2 } } { \sigma _ { 2 } ^ { 2 } }$
D) $p _ { 1 } - p _ { 2 }$