# Key Equations for Statistics

How is sums of squares worked out for within group?
Sum (Score - mean)2
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How is the sum of squares worked out for a between group?
(Mean of each group - Mean of Observed group)2 x N of pps in each group
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What is the equation for total sum of squares?
TSS = SSb + SSw
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How do you work out Mean squares?
SSW/D.F
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What is the degrees of freedom for MS between?
The number of groups -1
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What is the degrees of freedom for MS within?
The number of pps - Number of Groups
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How is F worked out in an ANOVA?
Between/Within
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What is a type 1 error?
False Positive
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What is a type 2 error?
False Negative
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What is the equation for the scheffe test?
(Mean of first sample - Mean of second sample)2/Within group variance (1/first sample + 1/second sample)
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Simplified way to work out scheffe
Square mean difference, then multiply it by number of participants, then divide by 2: Then this is divided by the Mean square Within: This is the reported scheffe
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What is the equation for a tukey test?
HSD = Square root (MS within/number of pps in group)
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Then what?
Compare this number with the different means, anything lower than this figure, is not significant
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What is the equation for a t-test?
Mean of group 1 - mean of group 2 / 2 x Square root (Ms error/n)
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How is the critical value of t found for multiple comparisons in the t-test?
P= 0.05/c
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What does C stand for?
Number of comparisons: Also known as the bonferroni correction test
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What is the four assumptions for the F ratio?
Independence, random sampling, homogeneity of variance and normality
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What is the equation for a Z score?
Z=Skew-0/SESkew
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How do you work out the SEskew?
Square root(6/N)
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What is the Z score associated with?
If Skew is greater than 1.96 then the sample is significantly different from normal
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What is a positive skew?
Higher than 1.96
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What is a negative skew?
Negatively higher than negative 1.96
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What is Eta squared?
N2 = SStreatment/SStotal
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## Other cards in this set

### Card 2

#### Front

(Mean of each group - Mean of Observed group)2 x N of pps in each group

#### Back

How is the sum of squares worked out for a between group?

TSS = SSb + SSw

SSW/D.F

### Card 5

#### Front

The number of groups -1