The Formula $\left( \frac { z _ { \alpha / 2 } \sqrt { \hat { p } ( 1 - \tilde { p } ) } } { B } \right) ^ { 2 }$

Essay

The formula $\left( \frac { z _ { \alpha / 2 } \sqrt { \hat { p } ( 1 - \tilde { p } ) } } { B } \right) ^ { 2 }$ is used to find the sample size needed to estimate a population proportion.In this formula,B represents the ____________________ on the error of estimation.