I’ve worked with various alternate file handlers in python before and wanted to explore the options in R. I was pleasantly surprised to find handlers prebuilt for tasks like compressing data. In addition, a pipe function is available to allow you to use less common commands on your file, like gpg for encryption.
I put together a quick video demo of how to use these functions, and it’s available on youtube:
The mean of means (of state e) is close to .36. If you take .3 * .36 + .4 * (1-.36), you get .364, so this seems to make sense. Note that I’m weighting the switching to e percentage based on the percentage of being in that state in the first place.
Note that I’m using the tm package, which is the traditional way to work with a document collection in R. There are new ways like tidytext that are gaining popularity. I may do a follow up talk on that.
The Monty Hall Problem is famous in the world of statistics and probability. For those struggling with the intuition, simulating the problem is a great way to get at the answer. Randomly choose a door for the prize, randomly choose a door for the user to pick first, play out Monty’s role as host, and then show the results of both strategies.
The numeric output will vary, but look something like:
One of the challenges of data science in general is that it is a multi-disciplinary field. For any given problem, you may need skills in data extraction, data transformation, data cleaning, math, statistics, software engineering, data visualization, and the domain. And that list likely isn’t inclusive.
One of the first questions when it comes to machine learning in specific, is “how much math do I need to know?”
This is where I would recommend you start, to get the most value for your time:
Matrix Multiplication (Subject: Linear Algebra)
Probability (Subject: Statistics)
Normal Distributions (Subject: Statistics)
Bayes Theorem (Subject: Statistics)
Linear Regression (Subject: Statistics)
Of course you will run across other math needs, but I think the above list represents the foundation.
If you need places to get started with those topics, check out Kahn Academy, Coursera, or your location library.