This data set was created using a random sample from the New Zealand Census At School 2003 database. I choose the 2003 survey as it has some interesting variables that I thought would be of interest to students working at curriculum level 3. The data cards are a mixture of pictures, words and numbers and before students use them they should work out the variables rather than being told what they are. I recommend reading the information about the data cards before using the data cards.

## Exploring relationships between two quantitative variables – progression part 1

I have been thinking about a progression for scatter graphs for a few months now. The big question for me has been what is the progression of ideas before we get to level 6. Through talking with others and reading extensively the following progression is mooted.

Curriculum level 4- introducing the idea of graphing paired quantitative variables, mostly through examples where we are looking at equivalence e.g. height = arm span. Leonardo da Vinci’s Vitruvian man is full of ideas about equivalent proportions of the human body and can provide a starting point for this sort of exploration. See My Modern Met website, click here for a fuller list of these.

These types of exploration allow students to start to explore using scatter graphs and thinking about where the pairs of data are equal, where one variable is larger than the other and vice versa. Looking at the difference between the two variables can be interesting as well and a useful additional analysis to do.

This video shows how to do this using CODAP.

Further ideas for level 4: this equivalence idea can be used for situations where students start to explore before and after data. For example looking at whether practice and instruction improves throwing and catching ability. Data about students throwing and catching ability is captured at the start of the unit of work. They engage in the unit of work designed to improve their throwing and catching ability. At the end data about their throwing and catching ability is captured. The paired data is shown in a scatter graph, differences are calculated and the difference is graphed. The two graphs provide a richer picture for description that either one by itself.

## Introducing the idea of finding the middle for data sets – video

This week while I have been at Concord Consortium in San Francisco I have spent much of my time making videos of recent activities that use CODAP. All of these activities I have been exploring with teachers and students in the work that I do.

Some of the earlier posts were about how to use CODAP:

- Getting started with CODAP
- how to use tables
- how to download data from another source and then upload into CODAP.

This video explores a teaching and learning idea for introducing early ideas of median. For New Zealand teachers this would be an activity I would do with curriculum level 3/4 students as they start to explore quantitative data and are looking for a signal as to the middle of the data that they have. CODAP allows us to put in a movable line and using counts it can be moved until about half the data is sitting on each side. I expand this to looking at the middle 50% of the data values and give examples of how to describe this. As this is aimed at curriculum level 3/4 the examples describe the whole group (Kowhai Whanau Group).

If you want to explore the data set used in the video you can get your own CODAP document to work on by clicking here. The data set used is a made-up data set using a random sample of students from CensusAtSchool.

## Getting data into CODAP from Census At School

This short video introduces the new random sampler tool on Census At School and shows how to download the data from Census At School and then import into CODAP to use for statistical analysis.

## Census At School 2019 data available now

Great discovery today when I went into the random sampler on Census At School, I found that the 2019 data base is there ready to use. Big shout out to the team at Census At School and to all the teachers and their students who participated in the census. Without all of the students there would be no data base, the teachers make this possible.

To find the database go to https://new.censusatschool.org.nz/explore/

Select download or explore a sample to see the new random sampler page which allows you to select the variables to explore without having to download and then tidy up the file before sharing.

## Census at School

The 2019 Census at School needs your students.