Handling Data 11
Find summary values that represent the raw data, and select the statistics most appropriate to the problem.
Select, construct and modify, on paper and using ICT, suitable graphical representation to progress an enquiry, including:
-line graphs for time series;
-scatter graphs to develop further understanding of correlation;
identify key features present in the data.
Interpret graphs and diagrams and draw inferences to support or cast doubt on initial conjectures; have a basic understanding of correlation.
Compare two or more distributions and make inferences, using the shape of the distributions, the range of data and appropriate statistics.
Communicate interpretations and results of a statistical enquiry using selected tables, graphs and diagrams in support, using ICT as appropriate.
What some should know
Identify possible sources of bias and plan how to minimise it.
Find the median and quartiles for large data sets; estimate the mean, median and interquartile range of a large set of grouped data.
-frequency polygons;
-lines of best fit by eye, understanding what they represent.
Analyse data to find patterns and exceptions, look for cause and effect and try to explain anomalies.
Examine critically the results of a statistical enquiry, and justify choice of statistical representation in written presentations, recognising the limitations of any assumptions and their effect on conclusions drawn.
What all should know
Decide which data to collect to answer a question, and the degree of accuracy needed; identify possible sources.
Collect data using a suitable method, such as observation, controlled experiment, including data logging using ICT, or questionnaire.
Calculate statistics, including with a calculator; recognise when it is appropriate to use the range, mean, median and mode.
Construct, on paper and using ICT:
-pie charts for categorical data;
-bar charts and frequency diagrams for discrete data;
identify which are most useful in the context of the problem.
Interpret tables, graphs and diagrams for discrete data and draw inferences that relate to the problem being discussed; relate summarised data to the questions being explored.
Compare two distributions using the range and one or more of the mode, median and mean..
What most should know
Suggest a problem to explore using statistical methods, frame questions and raise conjectures.
Discuss how data relate to a problem; identify possible sources, including primary and secondary sources.
Design a survey or experiment to capture the necessary data from one or more sources; determine the sample size and degree of accuracy needed; design, trial and if necessary refine data collection sheets;
construct tables for large discrete and continuous sets of raw data, choosing suitable class intervals; design and use two-way tables.
