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NZAMT NZQA NZ Grapher NZ Maths Census at School Study It Khan Academy Desmos

Writing a Statistical Report

Inference HOME | Achievement Objectives | Overview | Statistical Cycle
- Write an introduction | Using NZgrapher | Discussing sample statistics
- Box plots | Discussing the boxplot & dotplot | Sampling methods | Sample variability and size
- Informal confidence interval | Comparing two populations - discussion
- Writing a report | Revision


Writing up a report

Review of what is needed

Worksheet and answers on two examples of conclusions (link to mathstatsfacilitators web site)


Research Class notes, Blank notes

What is needed (handout)
Check list (reduced)


AS 2.9 Inference Checklist

Problem/Question (INTRODUCTION)
General introduction statement - what the report is about
- Variables defined with units
- Groups are defined.
- Population defined (and any assumptions)
- Formed a Comparative Research Question (Variable, groups, 'median', direction, population)
- A prediction is make: ‘I think that...’
- Reason why making your prediction: Why ‘I think that...’

Use iNZight to:
- Take a random sample,
- Analyse the sample
- Make a box & dot plot
- Display the informal confidence interval bars (save the display image)

Data / Display
- Did you have to ‘clean’ the data’ (discuss)
- Comment on the sampling method,
- Comment on the appropriateness of the sample size.

Analysis / Discussion
Discussion of the SAMPLE:
- Sample statistics comparing two groups.
- Distribution (dot plots) of the two groups symmetry, skew, outliers, gaps, clusters
- Box plots (Initial interpretation, Shape, Centre (middle 50%), Unusual aspects, Spread, Shift / Overlap)

The discussion needs be in context at all levels.
Also consider possible reasons or causes of these features (in the context)
‘I notice ... I expected ... I was surprised that...’

Discussing of sampling variability, including the variability of estimates (ESSENTIAL for Achieve)

Informal Confidence Intervals
- Discussion of what each informal confidence interval means
- Discussion of informal confidence interval overlap / or not
(in context & referring back to the population and how sure you are)
'I can be reasonably sure that...'

- Answer your research question by referring to your graphs, analysis and informal confidence interval.
- Make a conclusion about the population medians based on their samples taken from the population.
- Discuss errors, bias, omissions, improvements, further research...

- Discuss sampling variability, including the variability of the population estimates.
- An understanding relating to sampling variability and variability of estimates must be evident.
- Discuss the effect of different sample sizes

- Be sure to be clear when you are discussing the sample and when you are discussing the population estimate.








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