The Soybeans data fileatthebook’swebsiteshowsresultsofanexperiment22 to comparethe proportionsofsoybeanseedsthathavehealthyradicleofatleast2 mm after beingwrapped with wetgerminatingpaperundertreatmentAof25degreesCelsiusfor24hoursandunder treatmentBof20degreesCelsiusfor48hours.Thedatafilehasresultsfromaprivatelab and apubliclab(NationalInstituteofAgriculturalTechnologyinArgentina)ofthenumberof successes y out of n = 50 seeds for4replicatesand12cultivarsforeachtreatment.

(a) Statingassumptions,fitaGLMwithidentitylinkfunctiontomodeltheprobabilityof success intermsoftreatmentandlab.Interprettheestimatedtreatmenteffect.

(b) Showthatsignificantinteractionexistswhenweusethelogitlinkfunctionbutnotwith the identitylink.(So,itisplausiblethatthetwolabshavethesamedifferenceinsuccess probabilities betweenthetreatmentsbutnotthesameoddsratio;seeExercise7.33)