Cumulative Frequency

Teachers' Notes

The programme is intended to provide interesting and stimulating content that can be used to enhance other classroom work on this topic. It is assumed that students will have met grouped frequency tables prior to viewing and that they will be familiar with the median value. The programme shows how to find the 'middle value' using (n+1)/2 but points out that for large data sets n/2 would be sufficiently accurate. Some students may benefit from a fuller explanation of this idea, possibly prior to viewing.

The construction and interpretation of box plots is specifically covered. The UK National Sizing Survey is used as an example of a large data set and it is hoped that this will provide a contrast to the types of data that students can normally access. Students could consider what implications the difference in the distributions for inside leg measurements would have for retailers.

Since the programme focuses more on analysing data, it would probably be most useful to students who have already done some preliminary work on completing cumulative frequency tables and graphs. Detailed advice on using and reading from scales is not given and again, this is probably best covered in the classroom before viewing. The programme could be used to summarise the topic, or as a revision tool. Some students may benefit from viewing short sections as they progress through the stages of the work and then view the entire programme to summarise the main points.

Students could draw the box plot for the snakeboarding scores as a follow-up activity. The median was 46, the lower quartile was 36 and the upper quartile was 55. The lowest score was 8 and the highest was 83.