Problem of forgetting when scrolling the android check box

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler);
        recyclerView.setAdapter(new Adapter(createModels()));
    }

    private List<Model> createModels() {
        List<Model> models = new ArrayList<>();
        for (int i = 0; i < 100; i++) {
            models.add(new Model("Title " + i, new Random().nextBoolean()));
        }
        return models;
    }

    static class Adapter extends RecyclerView.Adapter<ViewHolder> {

        List<Model> models;

        Adapter(List<Model> models) {
            this.models = models;
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item, null));
        }

        @Override
        public void onBindViewHolder(ViewHolder holder, int position) {
            holder.bind(models.get(position));
        }

        @Override
        public int getItemCount() {
            return models.size();
        }
    }

    static class ViewHolder extends RecyclerView.ViewHolder {

        TextView textView;
        CheckBox checkBox;

        ViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.title);
            checkBox = (CheckBox) itemView.findViewById(R.id.checkbox);
        }

        void bind(Model model) {
            textView.setText(model.title);
            checkBox.setChecked(model.checked);
        }

    }

    static class Model {

        String title;
        boolean checked;

        Model(String title, boolean checked) {
            this.title = title;
            this.checked = checked;
        }
    }
}