msurvivingunitsareallremoved.ThemorderedobservedfailuretimesarecalledprogressivelytypeIIcensoredorderstatisticsofsizemfromasampleofsizenwithcensoringscheme(,...,mrr).Notethatifrr…mr,thenmrnmwhichcorrespondstothetypeIIcensoring,andifrr…mr,thennmwhichcorrespondstothecompletesample.Inthisstudy,weconsiderpointandintervalestimationsforthesimplestepstressALTwith()progressivetypeIIcensoring,()anexponentialfailuretimedistributionataconstantstress,and()thecumulativeexposuremodel.InSec.,wedescribethemodelandsomenecessaryassumptions.WeusethemaximumlikelihoodmethodtoobtainthepointestimatorsofthemodelparametersinSec..TheconfidenceintervalsforthemodelparametersarederivedinSec..AnumericaldatasetisstudiedtoillustratetheinferentialprocedureinSec...ModelandAssumptionsLetusconsiderthefollowingsimplestep-stressacceleratedlife-testingschemewithprogressivetypeIIcensoring:Supposenrandomlyselectedunitsaresimultaneouslyplacedonalifetesta