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Statistics: Statistical investigation

Level 1

AO1: Conduct investigations using the statistical enquiry cycle:

  • posing and answering questions;
  • gathering, sorting and counting, and displaying category data;
  • discussing the results.
This means students will collect, sort and count data. Students will mostly encounter category data. This data arises from classifying, for example sorting data into colour categories. Simple number data generated through measurement with whole units is also manageable. Students should become familiar with displaying category data using pictographs, set diagrams and bar charts. Discussion should centre on similarities and differences between categories, for example “Six more people like hokey-pokey ice cream than vanilla”.

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Level 2

AO1: Conduct investigations using the statistical enquiry cycle:

  • posing and answering questions;
  • gathering, sorting, and displaying category and whole-number data;
  • communicating findings based on the data.
This means students will use the statistical enquiry cycle in their investigations. The cycle has five phases that relate to each other. Some enquiries follow these phases in sequence but often new considerations mean that a statistician must go back to previous phases and rethink. The phases are:
statscycle.
At Level Two students should be able to pose questions that they want to investigate, consider the appropriate data they need to collect, gather and sort the data in order to develop an answer to their question. The data involved may be either category data or whole number data. Category data arises from classifying and the interest is in how many of the data items fall in each category (called frequency). Colour and number of doors are two ways to classify cars that will produce category data. Whole number data comes from situations where only whole number values are possible, e.g. how many people live in your house? or from rounding of measures, e.g. how long is your pencil to the nearest centimetre? The most common graphs for displaying category data are pictographs, bar, strip and pie graphs. Whole number data can be displayed using dot plots or stem and leaf graphs. Students should communicate their result through reference to their data displays with an emphasis on similarity and difference, e.g. boys like outdoor games more than girls..

Click to download a PDF of second-tier material relating to Level 2 Statistical Investigations (584KB)

Level 3

AO1: Conduct investigations using the statistical enquiry cycle:

  • gathering, sorting, and displaying multivariate category and wholenumber data and simple time-series data to answer questions;
  • identifying patterns and trends in context, within and between data sets;
  • communicating findings, using data displays.
The statistical enquiry cycle has five phases that relate to each other. Some enquiries follow these phases in sequence but often new considerations mean that a statistician must go back to previous phases and rethink. The phases are:

statscycle.

At Level Three students should be able to pose questions that they want to investigate, consider the appropriate data they need to collect, gather and sort the data in order to develop an answer to their question. The data involved should be multivariate so it should include many variables, e.g. gender, age, height, eye colour, bedtime, etc., so that relationships between the variables can be explored. Students should be able to ask summary questions (of a variable), e.g. what is the usual range in heights for 10 year old students?, comparison questions, e.g. are girls taller than boys?, and relationship questions, e.g. do older students go to bed later than younger students. Data displays, including tables and graphs, expected at Level Three are tally charts, frequency tables, pictographs, bar graphs, strip graphs, and pie charts for category data, dot plots and stem and leaf graphs for whole-number data, and simple line graphs for time series data. Students should be able to use computer technology to create these displays to find patterns, including trends over time, in data as well as to communicate their findings to others. They should be able to justify their choice of display/s with reference to the patterns they wish to highlight.

Click to download a PDF of second-tier material relating to Level 3 Statistical Investigations (171KB)

Level 4

AO1: Plan and conduct investigations using the statistical enquiry cycle:

  • determining appropriate variables and data collection methods;
  • gathering, sorting, and displaying multivariate category, measurement, and time-series data to detect patterns, variations, relationships, and trends;
  • comparing distributions visually;
  • communicating findings, using appropriate displays.
This means students will use the statistical enquiry cycle to plan and conduct investigations. The cycle has five phases that relate to each other. Some enquiries follow these phases in sequence but often new considerations mean that a statistician must go back to previous phases and rethink. The phases are:

statscycle.

At Level Four students should be able to pose questions that they want to investigate, consider the appropriate data they need to collect, gather and sort the data in order to develop an answer to their question. The data involved should be multivariate s (include many variables, e.g. gender, age, height, eye colour, bedtime, etc.) so that relationships between the variables can be explored. Students should be able to ask summary questions (of a variable), e.g. what is the usual range in heights for 10 year old students?, comparison questions, e.g. Are girls taller than boys?, and relationship questions, e.g. do older students go to bed later than younger students? They should be able to decide which variables are important for answering their question, e.g. quality of a sports player might be determined by points scored, assists, defensive turnovers or other variables. Students should also consider their methods of data collection, considering issues such as manageability, sampling, surveying, data safety, and technology use. Data displays, including tables and graphs, expected at Level Four are tally charts, frequency tables, pictographs, bar graphs, strip graphs, and pie charts for category data, dot plots, stem and leaf graphs and scatterplots for measurement data, and line graphs for time series data. Students should be able to use computer technology to create these displays to find patterns in the data, including differences and similarities between distributions, e.g. boys’ heights compared to girls, clusters and outliers within distributions, e.g. middle and spread, associations of variables, e.g. height with armspan, trends over time, e.g. cellphone use over a day, as well as to communicate their findings to others. They should be able to justify their choice of display/s with reference to the patterns they wish to highlight.

Click to download a PDF of second-tier material relating to Level 4 Statistical Investigations (185KB)

Level 5

AO1: Plan and conduct surveys and experiments using the statistical enquiry cycle:

  • determining appropriate variables and measures;
  • considering sources of variation;
  • gathering and cleaning data;
  • using multiple displays, and re-categorising data to find patterns, variations, relationships, and trends in multivariate data sets;
  • comparing sample distributions visually, using measures of centre, spread, and proportion;
  • presenting a report of findings.
Further detail on this Achievement Objective will be added shortly.

Click to download a PDF of second-tier material relating to Level 5 Statistical Investigations (288KB)

Level 6

AO1: Plan and conduct investigations using the statistical enquiry cycle:

  • justifying the variables and measures used;
  • managing sources of variation, including through the use of random sampling;
  • identifying and communicating features in context (trends, relationships between variables, and differences within and between distributions), using multiple displays;
  • making informal inferences about populations from sample data;
  • justifying findings, using displays and measures.
Further detail on this Achievement Objective will be added shortly.