Continuous Random Variables (Desmos)

I dislike education acronyms, but I can make exceptions for mathematical ones.  One of my favourite topics in A-level Maths is full to bursting with them: DRVs, CRVs, PDF, CDF.  This is a visual representation of the CDF (cumulative distribution function) of a CRV (continuous random variable), which is the function for the area under the curve from x=-∞ to any other value, a, or more specifically, P(X<a).  Take note of the syntax for piecewise functions.

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Beating the Odds

I was running a training session for new maths teachers last week and over lunch someone mentioned the weekend’s huge lottery draw, with the largest jackpot in UK lottery history of £66m, shared by two winners.  I remember when the National Lottery started, one of my first thoughts about it being, “if someone had enough money they could buy up every combination and guarantee the jackpot”.  We talked about this over our jacket potatoes with chilli and I started to consider the practicalities.  And, of course, the maths.  So here are my musings…

The Normal Distribution (Desmos)

Last year I made a couple of models on Desmos to demonstrate aspects of the normal distribution to my statistics students.

1.  Standardising

In this first one, you can set a normal distribution with any mean and standard deviation and then show what happens when you subtract μ and divide by σ to standardise the distribution (to do this, simply move the sliders).  It’s great because students can now visualise the procedure they are carrying out.