current implementation

// this goes in onCreate()
this.r1q1cb1 = (CheckBox) findViewById(R.id.cb1R1);
r1q1cb1.setOnCheckedChangeListener(cbRankedListener);

// ^..and so on for each checkbox

// checkbox listener
private OnCheckedChangeListener cbRankedListener = new OnCheckedChangeListener()
    {

        @Override
        public void onCheckedChanged(CompoundButton arg0, boolean isChecked) {
            // TODO Auto-generated method stub

            if(isChecked)
            {
                switch(arg0.getId())
                {
                case R.id.cb1R1:
                    r1q1cb1.setChecked(true);
                // here r[rank #1]q[ques #1]cb[checkbox No.#]
                    r1q1cb2.setChecked(false);
                    r1q1cb3.setChecked(false);
                    r1q1cb4.setChecked(false);
                    r1q1cb5.setChecked(false);
                    r1q1cb6.setChecked(false);
                    r1q1cb7.setChecked(false);
                    r1q1cb8.setChecked(false);
                    break;
                case R.id.cb2R1:
                    r1q1cb1.setChecked(false);
                    r1q1cb2.setChecked(true);
                    r1q1cb3.setChecked(false);
                    r1q1cb4.setChecked(false);
                    r1q1cb5.setChecked(false);
                    r1q1cb6.setChecked(false);
                    r1q1cb7.setChecked(false);
                    r1q1cb8.setChecked(false);
                    break;

            // and so on for other 6 checkboxes (total pair of 8)
}

            }
        }
    };