For72young girls sufferingfromanorexia,the Anorexia.dat file atthebook’swebsiteshows their weightsbeforeandafteranexperimentalperiod.Thegirlswererandomlyassignedto receivecognitivebehavioraltherapy(cb). familytherapy(f ), orbeinacontrolgroup(c).

(a) ConductanANOVAtocomparethemeanweightchangesforthethreetherapies.Inter-

pret the P-value.

(b) Useamultiplecomparisonmethodtoformconfidenceintervalscomparingthemean weightchanges,withfamily-wiseconfidencelevel0.95.Interpret.

(c) Regardingweightaftertheexperimentalperiodasthesoleresponse,fitalinearmodel with theinitialweightandthetherapyasexplanatoryvariables.Interpretthetherapyes-

timates. Conductinferencecomparingthetherapieswhileadjustingfortheinitialweight.

(The testcomparinggroupswhileadjustingforaquantitativecovariateiscalled analysis of covariance).