Stretch & Challenge – Mathematics

A really quick post this week, I see the Twitter #mathschat today is on Stretch & Challenge so I thought I would check some bookmarks I have saved; I will add some more references to this post in the next day or two and return to these later but in the meantime – some very useful links:

Colourful Chi Squared!

Updating a presentation, Colour in Mathematics or pdf version, Colour in Mathematics led to a happy find…

Chi Squared examplw

When teaching the Chi Squared test I have often found that students are not always clear on their interpretation of the contributions to the test statistic. A worked example with a little colour to help where we look at the observed data. the expected probabilities and the chi squared contributions seems to work well . This exercise made me realise that a chi squared calculator I had previously recommended did not seem to be working, so fortunately I found a better one!

From Social Science Statistics this Chi Squared Calculator is for a contingency table with up to 5 rows and columns. It is very simple to use, enter the group and category names, then the data, choose the significance level and calculate.
Chi Squared Calculator 1
Chi Squared Calculator 2

A clear conclusion is then given:
The chi-square statistic is 10.2061. The p-value is .037096.
The result is significant at p < .05.

The calculator is included on the Statistics 16+ page of Calculators & Tools.

Note the many other calculators  for statistical tests  available on Social Science Statistics.