median
don steward
mathematics teaching 10 ~ 16

Monday, 18 November 2019

introducing angles

a whole turn is 360 degrees because the Babylonians said it should be
a convenient number, given that you want to subdivide it

a ppt is here
















I've lost the source for these images - my apologies

seems to be BHC 2004?


see also spokes

Friday, 15 November 2019

Galton's quincunx

a neat introduction to theoretical probability distributions, starting experimentally

a ppt is here

teacher's guide

Sir Francis Galton
1822 ~ 1911

lived in Birmingham, UK

related to Charles Darwin

sometimes called a bean machine or a pinball machine







with a 4-row pinboard

















with different numbers of rows you obtain probabilities from a row of Pascal's triangle (over an appropriate power of 2)


why Pascal's triangle works, in this context
Pascal's triangle was known about long before Pascal...



















sheets for students to record their experimental and then, later, the theoretical pathways:






















there are various electronic versions of this on the net, that can be used for longer run simulations

these are from the 'math is fun' simulation
this is here

in spite of what books tell you, this illustrates how longer run experimental probabilities do not necessarily lead to more accurate results!






probability and venn diagrams

P(A) means the probability that a randomly picked person (from the entirety) is in set A

= n(A)/n(E)

Thursday, 14 November 2019

probability arrangements

a ppt is here
[needs to be downloaded for the animations to work]

arrangements (derangements)
factorials
pairing things off





what is missing?