Leider (app-name) aufgehört hat - Android-Entwicklung-Fehler

Lerne ich für das entwickeln von Android-Anwendungen und haben über ein problem in meinem ersten Projekt. Ich bin nach einem tutorial (Derek Banas) zu erstellen eine app, die ermöglicht es dem Benutzer, geben Sie etwas text ein, den Knopf drücken und dann die app-Ausgabe, die text.
Ich habe geschrieben, der code und habe keine Fehler, aber immer wenn ich die app laufen auf dem emulator, heißt es "Leider (app-name) hat aufgehört.
Hier ist die log cat:

08-23 17:51:36.026: D/AndroidRuntime(800): Shutting down VM
08-23 17:51:36.063: W/dalvikvm(800): threadid=1: thread exiting with uncaught exception     (group=0x414c4700)
08-23 17:51:36.196: E/AndroidRuntime(800): FATAL EXCEPTION: main
08-23 17:51:36.196: E/AndroidRuntime(800): java.lang.RuntimeException: Unable to start      activity ComponentInfo{com.nick.android.nick/com.nick.android.nick.MainActivity}:     java.lang.RuntimeException: Binary XML file line #12: You must supply a layout_height    attribute.
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.os.Looper.loop(Looper.java:137)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.ActivityThread.main(ActivityThread.java:5103)
08-23 17:51:36.196: E/AndroidRuntime(800):  at java.lang.reflect.Method.invokeNative(Native Method)
08-23 17:51:36.196: E/AndroidRuntime(800):  at java.lang.reflect.Method.invoke(Method.java:525)
08-23 17:51:36.196: E/AndroidRuntime(800):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
08-23 17:51:36.196: E/AndroidRuntime(800):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-23 17:51:36.196: E/AndroidRuntime(800):  at dalvik.system.NativeStart.main(Native Method)
08-23 17:51:36.196: E/AndroidRuntime(800): Caused by: java.lang.RuntimeException: Binary XML file line #12: You must supply a layout_height attribute.
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.content.res.TypedArray.getLayoutDimension(TypedArray.java:491)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.view.ViewGroup$LayoutParams.setBaseAttributes(ViewGroup.java:5820)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.view.ViewGroup$MarginLayoutParams.<init>(ViewGroup.java:5988)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.widget.LinearLayout$LayoutParams.<init>(LinearLayout.java:1831)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.widget.LinearLayout.generateLayoutParams(LinearLayout.java:1743)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.widget.LinearLayout.generateLayoutParams(LinearLayout.java:58)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.view.LayoutInflater.rInflate(LayoutInflater.java:757)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
08-23 17:51:36.196: E/AndroidRuntime(800):  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:267)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.Activity.setContentView(Activity.java:1895)
08-23 17:51:36.196: E/AndroidRuntime(800):  at com.nick.android.nick.MainActivity.onCreate(MainActivity.java:17)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.Activity.performCreate(Activity.java:5133)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
08-23 17:51:36.196: E/AndroidRuntime(800):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
08-23 17:51:36.196: E/AndroidRuntime(800):  ... 11 more