46. The following data refer to Stanford heart transplants. It relates the survival time of patients that have received heart transplants to their age when the transplant occurred and to a so-called mismatch score that is supposed to be an indicator of how well the transplanted heart should fit the recipient.

(a) Letting the dependent variable be the logarithm of the survival time, fit a regression on the independent variables mismatch score and age.

(b) Estimate the variance of the error term.

Transcribed Image Text:

Survival Time (in days) Mismatch Score Age 624 1.32 51.0 46 .61 42.5 64 1.89 54.6 1,350 .87 54.1 280 1.12 49.5 10 2.76 55.3 1,024 1.13 43.4 39 1.38 42.8 730 .96 58.4 136 1.62 52.0 836 1.58 45.0 60 .69 64.5