protected double[] checkWhetherRawItemsDichotomous(){

        if(!this.dichotomousCheckDone){
            this.dichotomous = new boolean[this.nItems];
            this.dichotomousPercentage = new double[this.nItems];
            int nDich = 0;
            for(int k=0; k<this.nItems; k++){
                this.dichotomousPercentage[k] = this.checkWhetherDichotomous(this.scores0[k]);
                if(this.dichotomousPercentage[k]==100.0){
                    this.dichotomous[k]=true;
                    nDich++;
                }
            }
            if(nDich==this.nItems)this.dichotomousOverall = true;

            this.dichotomousCheckDone = false;
        }
        return this.dichotomousPercentage;
    }