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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