Question

Recall the parallel lines model from the meadowfoam case study μ { Flowers! light,early)-Ao + Alight + Aearly where early was an indicator variable that took on the value 0 if the unit started light treatment at PFI and 1 if the unit started light treatment 24 days prior to PFI An alternative approach would be to use the "days before PFI" as a continuous time variable, i.e. time-24 for the units receiving light starting 24 days before PFI and time-0 for the units receiving light treatment starting at PFI A model then might be μ { Flowers lg ht ,time) = ⑩ + γ1 light + 72time (Note: I've used γ's instead of β's here to indicate the parameters in this model may not take the same values as in the previous model.) (a) Calculate the effect of the time variable in the above multiple linear regression, in terms of the parameters (b) An increase in time from 0 to 24 days is equivalent to an increase in early from 0 to 1, .e. the change in mean number of flowers going from time-0 to time-24 shuould be the same as the change in mean number of flowers going from early-0 to early-1. Use this fact along with your answer to part (a) to relate to 72 2

Answer 1