ViewModel Ошибка

Executing tasks: [:app:assembleDebug] in project C:\Users\user\Desktop\ViewModelExample-master

:app:preBuild UP-TO-DATE
:app:preDebugBuild UP-TO-DATE
:app:compileDebugAidl UP-TO-DATE
:app:compileDebugRenderscript UP-TO-DATE
:app:checkDebugManifest UP-TO-DATE
:app:generateDebugBuildConfig UP-TO-DATE
:app:prepareLintJar UP-TO-DATE
:app:mainApkListPersistenceDebug UP-TO-DATE
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources UP-TO-DATE
:app:mergeDebugResources UP-TO-DATE
:app:createDebugCompatibleScreenManifests UP-TO-DATE
:app:processDebugManifest UP-TO-DATE
:app:splitsDiscoveryTaskDebug UP-TO-DATE
:app:processDebugResources UP-TO-DATE
:app:generateDebugSources UP-TO-DATE
:app:javaPreCompileDebug UP-TO-DATE
:app:compileDebugJavaWithJavacC:\Users\user\Desktop\ViewModelExample-master\app\src\main\java\project\dajver\com\viewmodelexample\MainActivity.java:38: error: data has private access in ScoreViewModel
      model.data.observe(this, (s) -> {
           ^
1 error
 FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 1s
15 actionable tasks: 1 executed, 14 up-to-date

package project.dajver.com.viewmodelexample;

import android.arch.lifecycle.LiveData;
import android.arch.lifecycle.Observer;
import android.arch.lifecycle.ViewModelProviders;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class MainActivity extends AppCompatActivity {
TextView textView;

    private ScoreViewModel mViewModel;
    private int counterA;


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

        textView = (TextView)findViewById(R.id.textView);

        ScoreViewModel model = ViewModelProviders.of(this).get(ScoreViewModel.class);
        model.loadData();

      model.data.observe(this, (s) -> {

            textView.setText(s);
        });


    }


}

package project.dajver.com.viewmodelexample;

import android.arch.lifecycle.MutableLiveData;
import android.arch.lifecycle.ViewModel;
import android.os.AsyncTask;

import java.util.Random;

public class ScoreViewModel extends ViewModel {


    private MutableLiveData<String> data = new MutableLiveData<>();
    private MutableLiveData<Boolean> Loading = new MutableLiveData<>();

    public void loadData() {
        if (data.getValue() == null && Loading.getValue() == null) {
            new DataLoader().execute();
    }


    }


    private class DataLoader extends AsyncTask<Void, Void, String> {

        private String[] results;
        private Random random;

        public DataLoader() {

            results = new String[]{
                    "Success",
                    "Failture",
                    "BigData",

            };
            random = new Random();
        }
        protected void onPreExecute(){
            super.onPreExecute();

            Loading.setValue(true);
        }

        @Override
        protected String doInBackground(Void... voids) {
            return null;
        }

        protected void onPostExecute(String s){

            super.onPostExecute(s);
            Loading.setValue(false);
            data.setValue(s);
        }

    }


}