Q$5.$

The table given below shows the time to death $Y($in weeks$)$ and the white blood cell count $x($in thousands$)$ for a group of leukaemia patients. Interest lies in the estimation of exponential survival probabilities based on time to death data $Y,$ taking into account of the effect of the explanatory variable $x.$

$\backslash$table$[[x($WBC$,$ in thousands$),$Time to death $Y$