CONTROL CHARTS APPLYING A SEQUENTIAL TEST AT FIXED SAMPLING INTERVALS 37 be taken individually.and the fact that the sample That is.o and (1-)denote the significance leve the SPRT chart. The two-sided SPRT chart consti- a and the (A1 sfeodSpRrha - cure pape g is a rule that states:At stagej th ()accept Ho ifl≤r However t may be that for some (ii)reject.Ho if>a:or (ii)continue by observing if a that can be Thus,further sen to obtain the above error probabilities o aud d SPRT chart in which an upper bound is placed on the number of observations that may be aken a (1970) Next,it is shown that the conrrol statistics of the quality characteristic.There are many quality con upper and lower SPRT charts in (1)and (2).respe which sCpioportionaltothe (AD.the loglikelinood ratio can be and we will ent these that Stoum 2{2g-} for a generalization of the sprt chart and derive s zero-time and steady The ( 2-2+o- formal theoretical res arch on =2(")(-(")）a2 bout 194 with the fedWald's sPR LetK SPRT of be and identically distributed normal ran es with 6=2 (A3) decision for should be made with proha Similarly,for yo.=-(-go)/(20).and Vol.29.No.1.January 199 ournal of Quality Technology Reproduced with permission of the copyright owner.Further reproduction prohibited without permission.Reproduced with permission of the copyright owner. Further reproduction prohibited without permission