You run a movie empire, and want to build a movie recommendation system based on collaborative filtering. There were three popular review websites (which we'll call A, B and C) which users to go to rate movies, and you have just acquired all three companies that run these websites. You'd like to merge the three companies' datasets together to build a single/unified system. On website A, users rank a movie as having 1 through 5 stars. On website B, users rank on a scale of 1 - 10, and decimal values (e. g., 7.5) are allowed. On website C, the ratings are from 1 to 100. You also have enough information to identify users/movies on one website with users/movies on a different website. Which of the following statements is true?A) A. WRONG. You can combine all three training sets into one as long as your perform mean normalization and feature scaling after you merge the data. B) A. WRONG. It is not possible to combine these websites' data. You must build three separate recommendation systems. C) A. CORRECT. You can merge the three datasets into one, but you should first normalize each dataset's ratings (say rescale each dataset's ratings to a 0-1 range).D) A. WRONG. Assuming that there is at least one movie/user in one database that doesn't also appear in a second database, there is no sound way to merge the datasets, because of the missing data.

My favorite is "be concise."have you ever received an email and had to read a page full of information? by the time you finished reading it, you had to re-read it? i have even hit "reply" so that i could break it down into separate paragraphs and send it back to myself.what is concise? get to the point, fast. when opening an email like this, some will close it or print it to read later.i learned to use the subject line to prepare the reader for content. such as, "need on (blank), " "info only re: (blank)," "request input on (blank)," "read before (blank) meeting." these are just some.if you are asking for something, make that your first sentence. follow this by who, what, when, where, and how. use these, as necessary. example; (1) who (who needs it and or who does it), (2) what (specific description of what is needed), (3) when (specific, i need this by 8: 00 am monday or i need this by 10: 00 am today), (4) where (does it have to be printed and taken to someone, maybe the place of the meeting), (5) how (i need it scanned or faxed back to me at this email address, provide me with a hard copy).do not send yet. re-read it. did some spell check change a word? maybe let someone else read it for understanding. you want to avoid multiple emails asking for clarification. if important, put a read receipt on it. you will know it was opened, not necessarily read.end with a you.