Monday, December 17, 2018

NY Times Magazine Finds C.I.'s Baffling

Another journalist publicly declares their inability to understand the most basic math: in this case, confidence intervals. This is Statistics 101, people.
When I asked that representative to check with a supervisor, she did, then returned to tell me that the company’s certainty was 99.7 percent. Those answers were confusing, because behind each of Johnson’s percentages was a range from which each ancestry point was drawn. For example, when we clicked on Johnson’s Benin/Togo segment, which had been assigned 10 percent of her ancestry, the site showed that the percentage of her DNA from those nations could be as low as zero and as high as 21. In fact, every one of her African links showed a range that started with zero, while her Europe South’s percent had a range of 9 to 33. Even the customer-service representative agreed that it was hard to fathom that the company could be so certain about the percentage when the range behind it ran to zero, which it did in four of the six geographic findings on Johnson’s report. 

New York Times Magazine.

Monday, September 10, 2018

Why Do Nigerian Scammers Say They Are From Nigeria?

From 2012:
Far-fetched tales of West African riches strike most as comical. Our analysis suggests that is an advantage to the attacker, not a disadvantage. Since his attack has a low density of victims the Nigerian scammer has an over-riding need to reduce false positives. By sending an email that repels all but the most gullible the scammer gets the most promising marks to self-select, and tilts the true to false positive ratio in his favor.

Microsoft Research 

Monday, September 3, 2018

Dale Carnegie on Times Tables

Here's an excerpt from Dale Carnegie's uber-famous book, How to Win Friends and Influence People (Part 4, Section 8):
Clarence M. Jones, one of the instructors of our course in Cincinnati, Ohio, told how encouragement and making faults seem easy to correct completely changed the life of his son.

"In 1970 my son David, who was then fifteen years old, came to live with me in Cincinnati. He had led a rough life. In 1958 his head was cut open in a car accident, leaving a very bad scar on his forehead. In 1960 his mother and I were divorced and he moved to Dallas, Texas, with his mother. Until he was fifteen he had spent most of his school years in special classes for slow learners in the Dallas school system. Possibly because of the scar, school administrators had decided he was brain-injured and could not function at a normal level. He was two years behind his age group, so he was only in the seventh grade. Yet he did not know his multiplication tables, added on his fingers and could barely read.

"There was one positive point. He loved to work on radio and TV sets. He wanted to become a TV technician. I encouraged this and pointed out that he needed math to qualify for the training. I decided to help him become proficient in this subject. We obtained four sets of flash cards: multiplication, division, addition and subtraction. As we went through the cards, we put the correct answers in a discard stack. When David missed one, I gave him the correct answer and then put the card in the repeat stack until there were no cards left. I made a big deal out of each card he got right, particularly if he had missed it previously. Each night we would go through the repeat stack until there were no cards left.

Each night we timed the exercise with a stop watch. I promised him that when he could get all the cards correct in eight minutes with no incorrect answers, we would quit doing it every night. This seemed an impossible goal to David. The first night it took 52 minutes, the second night, 48, then 45, 44, 41 then under 40 minutes. We celebrated each reduction. I'd call in my wife, and we would both hug him and we'd all dance a jig. At the end of the month he was doing all the cards perfectly in less than eight minutes. When he made a small improvement he would ask to do it again. He had made the fantastic discovery that learning was easy and fun.

"Naturally his grades in algebra took a jump. It is amazing how much easier algebra is when you can multiply. He astonished himself by bringing home a B in math. That had never happened before. Other changes came with almost unbelievable rapidity. His reading improved rapidly, and he began to use his natural talents in drawing. Later in the school year his science teacher assigned him to develop an exhibit. He chose to develop a highly complex series of models to demonstrate the effect of levers. It required skill not only in drawing and model making but in applied mathematics. The exhibit took first prize in his school's science fair and was entered in the city competition and won third prize for the entire city of Cincinnati.

"That did it. Here was a kid who had flunked two grades, who had been told he was 'brain-damaged,' who had been called 'Frankenstein' by his classmates and told his brains must have leaked out of the cut on his head. Suddenly he discovered he could really learn and accomplish things. The result? From the last quarter of the eighth grade all the way through high school, he never failed to make the honor roll; in high school he was elected to the national honor society. Once he found learning was easy, his whole life changed."


Monday, August 27, 2018

Where Boys Outperform Girls in Math

Stanford study of some 260 million test scores shows that boys doing better than girls in math is related to their being in a rich, white, and suburban district. In poor and black districts, girls tend to do better than boys. This is distinct from English proficiency, which is constant across all these factors (girls always outperforming boys there):
The study included test scores from the 2008 to 2014 school years for 10,000 of the roughly 12,000 school districts in the United States. In no district do boys, on average, do as well or better than girls in English and language arts. In the average district, girls perform about three-quarters of a grade level ahead of boys.
But in math, there is nearly no gender gap, on average. Girls perform slightly better than boys in about a quarter of districts – particularly those that are predominantly African-American and low-income. Boys do slightly better in the rest – and much better in high-income and mostly white or Asian-American districts.
Note that this is synchronous with gender roles of parents in the given districts. In rich, white, suburban districts, parents are more willing to say they have egalitarian values, but actually more like to have traditional gender roles in the family (e.g., full-time working father and stay-at-home mother).

New York Times.

Monday, August 20, 2018

How to Document a Series of Button Clicks

Note to self: When documenting a series of interface button clicks for readers to follow, consider the following survey (in order of company sales/size in 2018):

In summary, I should (keep) using angle-brackets, as do the biggest 3 tech companies, instead of some other option.

Monday, July 23, 2018

17th Century Science Ciphers

Did you know? It was common in the 17th Century for scientists to publish cipher-versions of early findings, so as to establish priority in the discovery. (Something of an early, public-encrypted arXiv, as it were.) Huygens wrote in 1668:
a way of securing his discoveries and inventions for the future by way of cypher or anagram, to be lodged in the Register-book of the society, till he should think it convenient to explain them in a common language; making withal a beginning of this way of communicating new discoveries by sending the following cypher; which was ordered to be entered into the Register-book.

Stack Exchange: Skeptics.