Transcript AnalysisoftheHumanface4

Analysis of the Human face
9/26/06
Take-home Test
Due Friday!
• Today in class we will go over how to calculate group means and
standard deviations.
– This will be an exercise in the use of an excel database.
• For Friday, you are asked to calculate the means and standard
deviations for each group (A, B and C) separately, and then to perform
a t test on:
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A vs B
B vs C
A vs C
males vs females.
You should indicate which (if any) comparisons are significant at the 95%
confidence level.
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• Print your result and bring it to class on Friday.
– You will lose 10 points off your grade for each class period it is late.
• You can use the texts for reference, and I am available to help if it is
needed.
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Terashima_Satomi
Yoon_Christine
Zhang_Yu
Chai_Young
Fisun_Sergey
Jiang_Elise
Ko_Yeji
Lim_Sujin
No_Eul
Ross_Adair
Savitsky_Judith
Sun_Tianyang
Tan_Christopher
Variance in a Population
• where μ is the mean and N is the number of
measurements.
• It is computed as the average squared
deviation of each number from its mean.
– For example, for the numbers 1, 2, and 3, the
mean is 2 and the variance is:
A Cautionary Note
• The result differs from (X-m)2
[(1-2)+(2-2)+(3-2)]2 = 0
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• Be careful when calculating variance and
standard deviation.
– Most of the time we will let excel calculate for
us, but we should understand the calculation