Processing single and multiple variables. Module I3 Sessions 6 and 7. Learning objectives. Students should be able to: Provide and interpret the appropriate summary statistics for practical examples of quantitative data. Relate the general ideas of statistics
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Module I3 Sessions 6 and 7
We continue to use CAST in these sessions
Example using data from the statistics glossary
These terms all use Excel’s built-in functions
As we show on the next slide
The statistics as Excel functions
The terms should be (or become) familiar
From first principles
Reducing the vulnerability of the poor to current climate variability is the starting point for adaptation to climate change.
Climatic variability is a fundamental driver of poverty in poor countries. The climate is changing and it is highly likely that it will worsen poverty and hinder efforts to achieve the Millennium Development Goals.
The poor cannot cope with current climatic variation in many parts of the world, but this issue is often ignored in poverty assessments or national development planning.
Responses to existing climatic variability should be mainstreamed into national development plans and processes.
Current responses by individuals and governments to the impacts of climate variability can be used as the basis for adaptation to the increasing climatevariabilitythat will be associated with longer-term climate change.
Interpreting variability is so important
The start of the rains is important to many people
And is very variable from year to year
Consider the effect of “oddities” on the summary values
Sums of squares
Degrees of freedom
Total corrected sum of squares
devsq function in Excel – practical 1
d.f. = (n-1)
Overall mean square
This IS the variance
Residual (unexplained) or within groups sum of squares
Is much smaller than the overall SS
Residual mean square (residual variance)
Is therefore also much smaller than the overall variance
Overall standard deviation = √18.07 = 4.25
Residual (unexplained) standard deviation = √4.97 = 2.2
Is correspondingly much smaller
The next sessions show how to interpret the results as statements of risk etc