# 328. Slice of genius

So, I was doing my usual Human Piechart  activity when an interesting point occurred. I had the class split into a group of 20 and a group of 18 (I had a student in charge of each group so that the circles would be factors of 360). I asked the class how we could combine the groups to make a whole class pie chart. One student suggested we add together the angles and divide by two. Several other students agreed that it was a good idea.

There goes my lesson plan.

I put this prediction on the board and asked them to prove it or disprove it using hard facts. I was very impressed by the different techniques they used. Most students started by adding the angles and dividing by two, then:

• They went to the raw data and calculated the actual answers, disproving the prediction.
• Some looked at the angles on the ‘combined’ pie chart and worked out the number of degrees per person for each angle. They used the irregularities in angles to disprove the prediction.
• Looking at how many degrees there were per person and using logical deduction that you cannot add the angles.
• Others noticed that categories with the same number of people had different sized angles.

All this before they’d answered a single pie chart question! The moral of this story is: don’t ignore the wrong suggestions, embrace them and use student knowledge to dispel the myths.

# 304. S1 Revision Clock

If you are a regular on Twitter you may have seen some of the many revision clocks being shared. Basically 12 questions, 5 minutes each. Students can revise up to twelve different skills, under timed conditions, hence improving exam technique. My favourites are from the lovely Mel & Jo (@just_maths & @mathsjem). Not to be confused with Mel & Sue! (Random British humour/baking reference).

Image credit: www.cafepress.co.uk

• Mel’s blog post on revision clocks can be found here: Just Maths
• Jo’s collection of revision clock resources can be found here: Resourceaholic
• Don’t skip these links – they are good!

Now I used one of the C2 revision clocks with Y12. It was an eye-opener: some students were excellent at managing their time, some rushed the questions and wanted to move on (hence not checking their work and making daft avoidable mistakes like they have all year!), others gradually improved their time efficiency and a few ignored the time constraint and sat stuck on one question, when there were so many other questions they could have excelled at. Constructive feedback all round!

So I decided that we would do the same for Statistics. I put together a set of questions from Edexcel testbase – full credit to them is given on the sheets. They challenged my students due to the need for accuracy in calculations and the sheer laziness of not wanting to look up formulae. If you want to do the same, just download the resources here:

S1 revision clock (pdf)