Using graphing technology for

exploring the large data set

MEI Virtual Conference July 2020

Gerard Dummett

Education Manager, Casio

Why the large data set?

DfE

Specifications must require students to:

– become familiar with one or more specific large data set(s) in advance of the final assessment (these data must be real and sufficiently rich to enable the concepts and skills of data presentation and interpretation in the specification to be explored)

– use technology such as spreadsheets or specialist statistical packages to explore the data set(s)

– interpret real data presented in summary or graphical form

– use data to investigate questions arising in real contexts

Exam Boards

The large data set and associated contexts are explored in the classroom using technology, and that learners become familiar with the context and main features of the data (MEI)

Explore the data using appropriate technology … to enrich the teaching and learning of statistics, through which learners will become familiar with the context and main features of the data (OCR).

Build familiarity with the contexts, the main features of the data and the ways in which technology can help explore the data (AQA)

Support the assessment of statistics (Pearson)

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give a material advantage to students who have studied and are familiar with the large data set

What content is required?

Interpret diagrams for single-variable data

Interpret scatter diagrams and regression lines for bivariate data (calculations

are excluded)

Understand informal interpretation of correlation

Understand that correlation does not imply causation

Interpret measures of central tendency and variation, extending to standard

deviation

Calculate standard deviation, including from summary statistics

Recognise and interpret possible outliers in data sets and statistical diagrams

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What we’re doing today

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Use a handheld graphic calculator

to explore the LDS

Discuss some of the problems

surrounding interpretation

Consider how to engage students

in the statistical concepts

No experience of the calculator

required!

We will try to answer your

questions in the chat, and address

common ones at the end of the

session

Univariate (single variable) data

Extracted from the first MEI LDS

Data concerning countries of the world

Sampled median age of the population for each country in Africa and Asia

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Univariate (single variable) statistics

Africa Asia

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Interpreting a box plot - statistics brought to life

Much easier to interpret

Positive skewness in Africa - what does this mean?

Calculate using actual values

Questions that arise for investigation

– which countries are the outliers? Why?

– is age distribution different in other regions?

– has age distribution changed over time?

– what is the age distribution for individual countries?

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A bar chart helps to read the distribution

Positive skewness is a bit more

evident in Asia

There is a more equal distribution

of median age above the median in

Asia than in Africa

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Bivariate (two variable, paired) data

Extracted from the Pearson Edexcel LDS

Data concerning weather in locations in UK and 3 non-European countries

Extracted and cleaned daily mean wind speed and maximum gust speed at

Leuchars (Scotland), measured in knots

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Describe a relationship – scatter diagrams

What are the key issues?

What’s the expected relationship?

Which are the independent

(explanatory) and dependent

(response) variables?

What is the expected correlation

(positive, negative, none)?

Our investigation

Are gusts stronger on days when it is

more windy?

‘Gusts’ measured by maximum gust

speed

‘Windy’ measured by daily mean wind

speed

Independent: mean speed

Dependent: gust speed

Expected correlation: positive

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Scatter diagrams

There appears to be strong (or very

strong) positive linear correlation

between mean wind speed and

gust speed

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Correlation and regression line

Linear regression appears to be

appropriate

Correlation coefficient shows strong

positive correlation

Regression line is the (linear) line

that minimises the total (squared)

difference (residual) between the

line and the data points

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What does the regression line mean?

Equation of the regression line is

available and can be plotted

– be aware to interpret x and y in

context

The values of the coefficients of the

regression line have meaning

The regression line can be used for

predictions - provided inputs are

interpolated

Beware of extrapolation!

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What is the appropriate correlation?

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Always look at the scatter diagram!

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If you are interested in taking graphic calculators further

Our website has loads of support education.casio.co.uk

Training on the fx-CG50 is free /cg50-skills-training

Resources for skills and lesson ideas /resources

Emulators for your whiteboard /emulators

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