android studio 刚安装后创建了一个project 然后run模拟器 就出现这个问题求解答

Error:A problem occurred configuring project ':app'.
> Could not resolve all dependencies for configuration ':app:_debugCompile'.
> Could not find any version that matches com.android.support:appcompat-v7:15.+.
Versions that do not match:
23.1.0
23.0.1
23.0.0
22.2.1
22.2.0
+ 10 more
Searched in the following locations:
https://jcenter.bintray.com/com/android/support/appcompat-v7/maven-metadata.xml
https://jcenter.bintray.com/com/android/support/appcompat-v7/
file:/F:/Program Files/Java/jdk1.8.0_60/jre/bin/l/Android/sdk/extras/android/m2repository/com/android/support/appcompat-v7/maven-metadata.xml
file:/F:/Program Files/Java/jdk1.8.0_60/jre/bin/l/Android/sdk/extras/google/m2repository/com/android/support/appcompat-v7/maven-metadata.xml
file:/F:/Program Files/Java/jdk1.8.0_60/jre/bin/l/Android/sdk/extras/google/m2repository/com/android/support/appcompat-v7/
Required by:
MyApplication:app:unspecified

com.android.support:appcompat-v7:15.+ 这个是错误 在哪改

在gradle文件里，就在项目的根目录