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How reliable are our measurements? How do we know? How could we check?
Review the class master sheet. Are there any obvious errors?
Look at the data from 'Green Class'. On this spreadsheet, there are
so many numbers to add that the children have used the AVERAGE function.
In B28, the formula is:
=AVERAGE(B3:B26)
Show on the spreadsheet if possible, by clicking on any of the cells
containing the calculated results. Note carefully the syntax:
the colon indicates a range.
Division may yield a long string of decimals - readily encountered
on calculators! Show children how the result has been formatted to 0
decimal places (How to... sheet in preparation)
Look again at Green Class' sheet. Which column has been sorted?
In what order?
How accurate is this data? Draw attention to Emma's stride, Susie's
arm length. Suggest some more probable values and enter them. Note the
change to the average (mean).
Explain that pupils are going to set up a spreadsheet and enter the
data from their measurement survey, save the file and print out a copy.
On the computer, groups need to put in the headings for the columns
and the names of the children. Encourage co-operation: while individuals
take turns to enter the data, others may read out and check the screen.
Remind children to save their data regularly. Power cuts and system
crashes may be rare, but do cause loss of unsaved work.
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