## Probability screencast

This YouTube screencast runs through some basic ideas in probability for a GCSE Intermediate group.

- The probability scale
- Expected frequency
- Bags of balls
- Mutually exclusive events
- Possibility space diagrams
- Independent events

Each section has a white on black screen so students can find a section to review using the scroll control. The screencast was produced by ‘screencaming’ a PowerPoint that I used in a lesson. The PowerPoint was ‘presented’ in view mode and I added my commentary using a microphone. The iShowU screen cam software for Mac OS X detects the microphone and allows you to record the sound track directly. As you can tell if you listen, the commentary was unscripted (ahem) and the PowerPoint was essentially the same as used in the lesson, except I used screen grabs of the MS Excel simulation – I use that ‘live’ on the projector when teaching f2f in a whole group situation.

You can download the MS Excel spreadsheet with two probability simulations. The first worksheet has a table showing the result of tossing 100 coins (press F9 for a new toss). The second worksheet shows the number of heads in of 100 trials each of 30 coin tosses as a line chart.

These screencasts are relatively quick to produce and might help students revise or catch up. I have mentioned the iShowU software from Shiny White Box in a previous post. I also mentioned the Video2SWF software that allows you to produce Flash movies that are not hosted by YouTube as well.