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What is ORA?
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P-hacking
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How PEBBA works
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What is ORA?
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P-hacking
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How PEBBA works
Over Representation Analysis
ORA is a statistical method that determines whether genes from pre-defined sets are present more than would be expected in a subset of your data
Hipergeometric Test
Hipergeometric Distribution
Pr(X=k)=\frac{ \binom{K}{k} \binom{N-K}{n-k}} {\binom{N}{n}}
N: Number of genes
K: Number of genes in a group
n: Number of differentially expressed genes
k: Number of differentially expressed genes in that group
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What is ORA?
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P-hacking
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How PEBBA works
Multiple Comparisons
Multiple Comparisons
Spurious correlations
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What is ORA?
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P-hacking
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How PEBBA works
GMT
DEG
GMT
DEG
\(\pi\_value = -\log_{10}(p\_value) \cdot \log_2 FC\)
Quick Demo
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By barzilay
