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11.2 years ago
snp_cook12
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0
hello, I have a question, how do you inverse normally transform a quantitative trait for genetic association studies?
hello, I have a question, how do you inverse normally transform a quantitative trait for genetic association studies?
Here's a nice paper on Pubmed Central discussing issues surrounding inverse normal transforms. In general, the idea is to match the normalized rank of the trait to a quantile in a normal distribution. Have a look at equation 1 in the paper I linked to.
I think the paper mentioned by Devon Ryan worths to read.
To do INT(inverse-normal transformation), you can use the R code below:
qnorm((rank(x,na.last="keep")-0.5)/sum(!is.na(x)))
See the supplement of this paper - Yang et al. Nature 2012.
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