Aug 23, 2017 Part 2: the t-Distribution We saw in the previous post that if X is a random variable and the population distribution of X is normal with mean $$\mu$$ and standard deviation $$\sigma$$ (variance $$\sigma^2$$), then the distribution of the sample mean $$\bar{X}$$ for samples of a given size $$n$$ is normal, with mean $$\mu$$ and standard deviation of $$\frac{\sigma}{\sqrt{n}}$$, which we can write $$\bar{X}_n \sim N(\mu,\frac{\sigma}{\sqrt{n}})$$.1 More exciting, we saw that by the Central Limit Theorem, the sampling distribution will be normal regardless of the original population distribution if the sample size is large enough. ...
Aug 8, 2017 Hello! This is the first in a series of posts that cover topics typically encountered on any Introduction to Statistics course syllabus (yes, that is to say frequentist). The idea was born out of a desire to blog about the Analysis of Variance and its many forms, but I soon found myself addressing pre-requisites, which led to tangents and lemmas that took on lives of (and ballooned into posts of) their own. ...
Jul 17, 2017 In less than two day’s time, I was able to purchase my third computer from a perfect-craigslist-stranger (without issue!) and replace the hard disk with a solid state drive, and I wanted to take a minute to document the experience here; if you are interested only in a rough guide for SSD installation for a 2017 HP laptop, you are heartily encouraged to skip down several paragraphs. The computer in question is an HP 15-ba113cl that the original owner bought in February 2017 from our local Costco for around \$400. ...
Aug 4, 2016 My wife Lindsay let me co-blog about fixing up a century-old sewing machine! Check it out here: http://www.lindsaywoodward.com/2016/07/cleaning-and-operating-a-100-year-old-sewing-machine.html/
Jun 1, 2016 The Memory Dynamics Laboratory is having something of a book club this summer, but the crucial volume was proving difficult to find; it had been out of print for many years and the UT library system only has a single copy! I proudly volunteered to do the hunting-up and ferreting-out because I have at my disposal a skill-set unique to the hyper-stingy tech-savvy long-term student, i.e., time-honored and hard-won methods for coaxing any book I please from the depths of the internet (way too many hyphens going on here). ...
Aug 30, 2015 Every couple of days I force myself to go outside and run about 2-4 miles. I do not enjoy it. It makes me feel like I am dying every time; I gasp and wheeze and, even after showering I stay uncomfortably sweaty for a few hours. Worse still, I do not feel “energized” or whatever other vital sensations people claim to derive from exercise; if anything, I feel especially fatigued afterwards, and this only gets more pronounced as the day progresses. ...
Aug 29, 2015 "...There is this collection of ultimate scientific questions, and if you are lucky to get grabbed by one of these, that will just do you for the rest of your life. Why does the universe exist? When did it start? What’s the nature of life?... The question for me is how can the human mind occur in the physical universe. We now know that the world is governed by physics. ...
Jul 1, 2015 This book made me think new thoughts; this is rare, so I am posting about it. If you read nothing else in the post, read the end. “A New Kind of Science” is a 13-year-old book preceded, and regrettably often prejudged, by its reputation. Many of the criticisms that have come to define the work are valid, so let’s get that part out in the open. The book can be read in its entirety here; it is enormous, both physically (~1,200 pages) and in scope, which has led to a limited and specialized readership lodging many legitimate, though mostly technical, complaints. ...
Jun 21, 2015 It’s not everyday that I want to read something a Pope wrote. In fact, today, June 19, 2015 was the only day I have ever wanted that, if memory serves. Today I read Papa Francesca’s second encyclical, entitled “Laudato Si – On Care For Our Common Home”. It was a unique experience to navigate to w2.vatican.va, download an essay the Pope just wrote about environmentalism, and then read it on my computer. ...
Jun 14, 2015 "With one singular exception, time’s arrow is straight. Unidirectionality of time is one of nature’s most fundamental laws. It has relentlessly governed all happenings in the universe... Galaxies and stars are born and they die, living creatures are young before they grow old, causes always precede effects, there is no return to yesterday, and so on and on. Time’s flow is irreversible. The singular exception is provided by the human ability to remember past happenings. ...