If we knew two pth quantiles for a normal distribution, is it possible that we can find mean and sigma for the normal distribution using R? Let x ~ norm(mean, sigma). Suppose that qnorm(0.9,mean,sigma) and qnorm(0.1,mean,sigma) are known. Can we find mean and sigma using R? Thanks, -james
Normal distribution with R
2 messages · guox at ucalgary.ca, Eik Vettorazzi
Hi James its just simple calculus, since with q90<-qnorm(.9,me,sd) q10<-qnorm(.1,me,sd) mean<-(q90+q10)/2 # the normal distribution is symmetric around the mean sd<-(q90-q10)/ (qnorm(.9)-qnorm(.1)) # between 10th and 90th are qnorm(.9)-qnorm(.1)=2.563103sds hth. guox at ucalgary.ca schrieb:
If we knew two pth quantiles for a normal distribution, is it possible that we can find mean and sigma for the normal distribution using R? Let x ~ norm(mean, sigma). Suppose that qnorm(0.9,mean,sigma) and qnorm(0.1,mean,sigma) are known. Can we find mean and sigma using R? Thanks, -james
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