If The $100 ( 1 - \alpha ) \%$ Confidence Interval $\left( \hat { \beta } _ { 0 } + \hat { \beta } _ { 1 } x ^ { + } \right) \pm t _ { \alpha/2 , n - 2 }$

Essay

If the $100 ( 1 - \alpha ) \%$ confidence interval $\left( \hat { \beta } _ { 0 } + \hat { \beta } _ { 1 } x ^ { + } \right) \pm t _ { \alpha/2 , n - 2 }$ . For the expected value of Y when $x = x ^ { +}$ is computed both for x = a and for x = b to obtain joint confidence intervals for then the joint confidence coefficient on the resulting pair of intervals is at least __________ %.