Minor changes for the interfaces updated

See merge request !80

Minor changes to inerfaces

See merge request !79

Integrate Probability Calculation and Probability Calculation input method

See merge request !77

Updated code for probability calculation

See merge request !78

# Conflicts:
#	app/build.gradle

Create function for Probability calculation and normal distribution

See merge request !76

# Conflicts:
#	app/build.gradle

# Conflicts:
#	app/build.gradle

# Conflicts:
#	app/build.gradle

# Conflicts:
#	app/build.gradle
#	app/src/main/AndroidManifest.xml

# Conflicts:
#	app/build.gradle
#	app/src/androidTest/java/com/elearning/probabilityandstatisticsanalyserandeducator/WelcomeTest.java
#	app/src/androidTest/java/com/elearning/probabilityandstatisticsanalyserandeducator/adaptiveLearning/StartingScreenTest.java

Recommendations are working

See merge request !75