Stevejobs data:

I am honored to be with you today at your commencement from one of the finest universities in the world. I never graduated from college. Truth be told, this is the closest I've ever gotten to a college graduation. Today I want to tell you three stories from my life. That's it. No big deal. Just three stories. The first story is about connecting the dots. I dropped out of Reed College after the first 6 months, but then stayed around as a drop-in for another 18 months or so before I really quit. So why did I drop out? It started before I was born. My biological mother was a young, unwed college graduate student, and she decided to put me up for adoption. She felt very strongly that I should be adopted by college graduates, so everything was all set for me to be adopted at birth by a lawyer and his wife.

Steve Jobs, chairman, chief executive officer (CEO), and co-founder of Apple Inc., provided the commencement speech for Stanford University graduates on June 12, 2005. The famous phrase "Stay hungry, stay foolish" was included. The attached text file named "SteveJobs.txt" includes a complete text of the speech. We would like to investigate this speech to see how many different topics he tried to deliver, so it requires text analysis using the Latent Dirichlet Allocation (LDA) technique. Please conduct the following task using R. a. Find the optimal number of topics k for the text data ( 10pts). b. Display the term-probability and document-probability by setting the number of topics at k ( 10pts)