to have an, idea about the relation between the length of birth interval and lactation, and birth control program this study have been done. the material for such analysis was nomad women's fertility history that was in their reproductive period (15-44). the material itself was gathered through a health survey. the main sample was composed of 2,165 qualified women, of whom 49 due to previous or...

in this paper we nd solution of linear interval equation in dual form based on the generalizedprocedure of interval extension which is called interval extended zero method.moreover, proposed method has signicant advantage, is that it substantially decreasesthe excess width eect.