A name is vital


Students learn what vital statistics are, and that Statistics New Zealand collects and collates these data. The focus is for the student to present and communicate a chosen aspect of population statistics in the most appropriate graphic way, and to explain and justify their choice of visual display.

Achievement Objectives
S3-2: Evaluate the effectiveness of different displays in representing the findings of a statistical investigation or probability activity undertaken by others.
Specific Learning Outcomes
  • display collected data in an appropriate format
  • produce bar charts of data using Microsoft Excel
  • make statements about implications or possible events based on selected data
Description of Mathematics

The focus of level 3 investigations is typically expanding from exploring information about themselves and their immediate world, to exploring information in the wider world.

Accordingly, in this unit the student is developing an understanding of vital statistics (quantitative data concerning the population, such as the number of births, marriages, and deaths), of where these can be located, of how useful and interesting they can be, and how best to represent these data visually.

As students are exposed to a range of population data they should select data of particular interest to them, consider and choose the visual data display that would best present the numeric information.

They should call and build upon their level 2 knowledge and use of frequency tables, 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 and be able to communicate their findings to others. They should be able to justify their choice of display/s.


The Department of Internal Affairs registers births, deaths and marriages (BDM) and maintains NZ birth, death, marriage, civil union and name change information, and issues certificates and printouts. 

The registration number is a unique number allocated to every registered birth, death, marriage or civil union,
Information on the number of births and deaths registered in New Zealand is published once a year: 
Statistics on the number of marriages, civil unions, and divorces registered in New Zealand is also released annually:

Required Resource Materials
  • Access to the internet
  • Graphing materials (either Excel or similar or graph paper etc.)

Session 1:

As a class:

  1. Begin by linking to the online population clock.
    Note together the total population and that the vital information presented is births and deaths.
    If possible, wait till one of the totals changes (the ‘population clock ticks over’) and talk about what has happened.
    Explain that a birth or death must be registered.
  2. Ask what they think the letters BDM stand for (births, deaths, marriages) and what vital means, (absolutely necessary; essential).
    Have students explain to each other what vital statistics are, and suggest where data for NZ might be found.
  3. Together visit, explore and discuss:
    Ask how these data/statistics are gathered. (You are legally required to register BDM).
    Make clear that this information is collected as it occurs, unlike census of population and dwelling which is carried out every 5 years information in NZ.
  4. Together visit, explore and discuss the Department of Internal Affairs site:
    Together read the services that BDM provides and point out that family history can be explored using this database.
  5. Brainstorm the kind of information that might be collected in a census: (Population and dwellings, Age and sex, Cultural diversity, Relationship status, Qualifications, Work, Income, Families, Households, Phone,fax, internet,Transport, Housing, Business) and the types of questions that might be asked. 

Session 2.

Have students work in pairs with online access:

  1. Access and explore nz census cultural diversity statistics:
    Have students look at the way in which the numeric data are presented on the tables (some include category totals with percentages, and others present changes to the totals of variables that have change over (3) years).
    Discuss percentages and, as appropriate, review how to calculate percentages on a calculator.
  2. Have each student identify a data set which is of particular interest to them. List types of possible data displays and have students discuss with their partner the best display to use for their chosen data set.
  3. Each student should plan and create a graph which best displays their chosen data set. They should write accompanying statements about the data, make inferences or predictions if appropriate, and record the reasons they chose the particular display.
  4. Have students present and share their work. They should read and critique each other’s displays and, where an incorrect choice is made, suggest a more appropriate format. 

Session 3.

Individually or in pairs:

  1. Access and explore the first name spreadsheet:
    Ask students if these data are vital statistics.(No, these data do not show numbers of BDM)
    Have students locate data for their own birth year, and for that of a parent or grandparent if they know this.  
  2. Have students suggest an investigation they could undertake: For example.
    How many students in the class/school share the same birth year as the investigating student?
    What fraction or percentage of these names are in the top 10% (20% or 50%) of the most popular names recorded in NZ for that birth year?                        
    What fraction or percentage of student names are not listed at all in the data list for that year. Why might that be?
  3. Students plan their investigation in pairs. Plans are then discussed. (It is likely that one well planned and coordinated survey or data gathering exercise will serve to gather the data to answer all questions.) 
  4. Have them carry out their investigation and share their findings.
  5. Reflect on the name data that can be generated from the compulsory registration of births. Have students suggest other data that may be of interest.
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Level Three