Sam's Blog

Today: this visualization of conditional probability Figure out what's going on; be able to explain it. You can discuss it in groups. Then, work on anything that's fallen through the cracks... data gathering, old homework. If you are caught up, we can start on the Feltron projects.

nom nom nom! Pre-Intro How goes the data gathering? Any hiccups I can help with? I haven't heard anything from anyone, so I will assume the class is going well. Let me know if there are problems. They're with the class, not you. Intro hmmm...nothing seems to be here... Main Hey, so, remember geometry? Here's a summary: shapes and their properties. One of those properties is area; it's how much space something flat (two dimensional (2D)) takes up. So, a line doesn't have area, and neither does a ball, because neither are flat (in the sense of being 2D; the line is one dimensional, the ball is three). However, the following do have area: triangle rectangle circle trapezoid If you haven't seen any of these formulae before, just ask me if you have questions. Anyway, you should really know those. I will tell you them when I ask geometry questions, but, like vocabulary, there are certain math concepts that you're just expect...

[NOTE: Skim this whole post before  doing the work; I promise it's a good idea.] How can you get a feel for probability? It's all well and good to say the probability of getting heads is 1/2, but we know that if you flip a coin 2 times, you aren't guaranteed to get one heads and one tails. We could  flip a coin 10 times and get all 10 heads. It feels less likely that if we flip a coin 100 times, all 100 will be heads... but at this point our intuition starts to fade. So we simulate! Plan Open Google Drive and start a new spreadsheet Use the function RANDBETWEEN(smallNumber, bigNumber) to make a random number that is either 0 or 1: 0 for tails, 1 for heads. Use the function IF(test, valueIfTrue, valueIfFalse) to make a column that says "Heads" or "Tails" depending on the first column. Use conditional formatting to highlight heads. Look for streaks.  Next As of 2014, in America, the odds of dying are 864 in 100,000. That is, in an overs...

Instead of a gif, here is a little peak of "math is crazy and awesome and beautiful." The audio is just quiet music, so you can watch it on mute without missing anything. Have you been keeping track of your data? Show me! Ok, so, we will talk about the passcode breaking today. I am going to write a summary of my explanation below, in case anyone is absent or needs review. But I'll be honest, don't just read it. Write things down, and look and think on them, because this is not obvious stuff. Today talk about how we thought about the homework talk about factorial make a spreadsheet that calculates factorial from a list of numbers, without using the built in function (homework) Tomorrow more spreadsheets, less KA for a while ==== Below this is an explanation of the passcode breaking ===== This is not the most mathematically efficient way to calculate it... But it feels like a good balance between using math to save time, and still being unde...

Imagine a lock with a 4 digit passcode: Now imagine that you have some fancy spy technology and you can put on some goggles and see which keys have been pressed, but not the order, or number of times they were pressed. If you see this, how many possible passcodes are there? Homework: What if two keys have been pressed? Three?

Ok, I am asking you to really try in this class. I am not expecting you to pick everything up easily, and when you get stuck and need to ask questions, that's not a problem. It's expected. The following two questions are from beanactuary.com (that's Be An Actuary dot com, not Bean Actuary .com. I think): 1. An urn contains 10 balls: 4 red and 6 blue. A second urn contains 16 red balls and an unknown number of blue balls. A single ball is drawn from each urn. The probability that both balls are the same color is 0.44. Calculate the number of blue balls in the second urn. Hint: using the words "and" and "or", what does it mean to say that "the probability that both balls are the same color is 0.44." Also, you have to use a little bit of algebra. 2. An insurer offers a health plan to the employees of a large company. As part of this plan, the individual employees may choose exactly two of the supplementary coverages A, B, and C, or t...

Class and homework: Get caught up. Finish these exercises and anything else you haven't done Dependent vs Independent events Dependent Probability Multiplying dependent probabilities Basic set notation

Let's do a little work Adding Probabilities Independent Probability Probabilities of Compound Events

Hey! Let's start out the day by recording data for the Feltron, if you haven't already. Then let me know where you are, homework-wise. Now let's talk correlation vs. causation. Correlation When two things change together, we can use a fancy word and say they are correlated. When things are correlated, if we know one, we automatically  know the other, at least somewhat. Here's what I mean: If I tell you that a human exists, you don't know much about their weight. The smallest baby ever born (and survive), Rumasia Rahman, weighed a little more than 0.5 pounds (lbs). Jon Brower Minnoch, on the other hand, was the heaviest person ever, and weighed 1,400 lbs at his heaviest. That means that if all I tell you about someone is that "they are a person", and ask "what do you think they weigh?" you only know they weigh between 0.5 lbs and 1,400 lbs - though they probably weigh somewhere in between, 100-200 lbs. However, if I tell you that the ...

mmmm.... Sam is not here, so be nice to your sub. Record your Feltron data and work on  the seven Statistical Studies exercises on Khan Academy . If you finish, please don't become a disturbance. It would be rude, and people would judge you. You can: do work for another class, or work on review on Khan Academy. If you want more statistics, read this amazing book, Statistics Done Wrong . Of course, you may not finish in class, in which case just finish it for homework. Or rather, spend an hour at home, and if you don't finish, let me know. Also, if you are struggling, you can email me questions, but be specific. Please do work. Please don't distract your classmates. If you're done, offer help; if you're having trouble, ask for help!

Ok, today didn't go exactly as planned. If you saw the blog post I had up planned for today... we will get to that, but I incorrectly estimated how long some work would take you. Not your fault. You guys just move so fast through most material! You are working on the  Statistical Studies topic  on Khan Academy. It is not easy. That is okay. You don't have to get frustrated, or discouraged, or stressed. If it takes longer than I thought it would, I'll give you more time. Some good insights from the classwork: Go straight to the exercises, but go back to the videos if you are stuck If the videos feel too long, you can speed up playback (in the options menu, click the gear button). 1.25x isn't even noticeable. 1.5x is, but if you listen for a while you get used to it and can switch to 2x An "experiment" involves splitting a subset of the population you are looking at into two groups: one called the "control", who don't do anything diff...