Ecological Genetics

1
Ecological Genetics Lab 1 An introduction to
variance
2
Types of data
Categorical
Continuous
3
Descriptive statistics
Frequency or
Mean and the variance
Categorical
Continuous
Number of moths
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Transformation of data can improve normality
Raw data
Square root
Log
x0.25
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Descriptive statistics
Mean
µ
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Different means Same variance
Different variance Same mean
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Variance
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Variance

• Will also be called the mean square
• Units of measurement squared (i.e. cm2)
• Standard deviation is the square root (units cm)

Also symbolized by ?2 s2
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• Calculate the mean
• Calculate the deviation from the mean
• Square the deviations
• Sum them up (called the sum of squares)
• Divide by n-1