How to checkbox set checked by clicking on button which is place in another class

I have 2 activity i make a Checkbox and button in same activity when i click on button the checkbox is mark checked automaticaly.my problem is i want this button in another activity .now i use this code public class MainActivity extends Activity {

CheckBox mCheckBoxRegular;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mCheckBoxRegular = (CheckBox) findViewById(R.id.checkBox1);

    Button regular = (Button) findViewById(R.id.button1);

    regular.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            mCheckBoxRegular.setChecked(true);

        }
    });

}

}