Which of the Following Would Be a Measure of Spread $\sum X _ { i } \cdot P \left( X _ { i } \right)$

Multiple Choice

Which of the following would be a measure of spread of a probability distribution.

A) $\sum X _ { i } \cdot P \left( X _ { i } \right)$
B) $\sum X _ { i } ^ { 2 } \cdot P \left( X _ { 1 } \right)$
C) $\sum \left( K _ { i } - \mu \right) \cdot P \left( K _ { i } \right)$
D) $\sum \left( X _ { 1 } - \mu \right) ^ { 2 } \cdot P \left( X _ { 1 } \right)$