Browsing All Posts filed under »random-number functions«

Using summary tables in simulations

August 17, 2012


In the apstat community thingy, Rudy Medina posted a problem, and Paul Myers posted a solution. I’ll show another solution, and maybe veer off into philosophy. Here’s the problem (from 16 August 2012): A bus stop has 7 stops and 4 passengers.  If every passenger is equally likely to get off at any stop, what is […]

Streak Lengths

August 14, 2012


We humans see streaks as indications of non-randomness, but streaks do occur in genuine random phenomena—usually more than we think. There are famous activities about this, like the one where you ask students to (secretly) create “realistic” sequences of 100 heads-or-tails coin flips along with genuine sequences from a fair coin. The wise, omniscient teacher […]

The Key to the Birthday Problem: uniqueValues( )

May 30, 2012


It’s a famous probability problem: given N people in a room, what’s the probability that at least two of them share a birthday? It’s famous because the answer is often surprising: a remarkably small number (23) will give you a probability over 50%. How do you simulate it in Fathom? The key is going to be […]

Exponential Decay Simulation

May 9, 2012


This comes from a Fathom listserv query by David Petro: 1. Flip 1000 coins 2. Remove the heads and count up the tails 3. Flip the remaining tails again 4. Repeat 2 & 3 until no coins remain 5. Graph the number of tails after each experiment. This is what I have tried I Have […]

Make Your Own Binomial Machine

May 2, 2012


Here’s how to make a Fathom simulation that will let you change the parameters of a binomial distribution quickly. Note that this may not be best for instruction. In a new document, make two new sliders, N and p. Make a table and give it 1000 cases. Make one attribute (call it successes or anything you […]