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What use are Z-scores with not normal data?
In some applications (such as weight-for-age in nutritional studies), the Z-scores are not based upon the known population mean and standard deviation, but on an external reference population. In this situation the Z-scores are used to identify those individuals in the sample falling below a specified Z-score.
Can you use z scores for non normal distribution?
A Z-score is a score which indicates how many standard deviations an observation is from the mean of the distribution. Z-scores tend to be used mainly in the context of the normal curve, and their interpretation based on the standard normal table. Non-normal distributions can also be transformed into sets of Z-scores.
Can you use z-score if distribution is not normal?
Non-normal distributions can also be transformed into sets of Z-scores. In this case the standard normal table cannot be consulted, since the shape of the distribution of Z-scores is the same as that for the original non-normal distribution.
Can a z score be used for non-normal distributions?
Z-score is meaningful for all sorts of distributions, but its meaning isn’t identical. Yes—by using Chebyshev’s inequality (aka “Chebyshev’s Rule”). This inequality is valid for any distribution, and gives somewhat useful bounds on where data can lie.
Can a z score be used with skewed data?
If X is highly skewed the Z statistic will not be normally distributed (or t if the standard deviation must be estimated. So the percentiles of Z will not be standard normal. So in that sense it does not work. The R code will work, but the z-score will be about as meaningful as the sentence “Grapes are phoning the fountain pen lightly.”
What are the different types of non normal distributions?
There are many types of Non-Normal distributions that a data set can follow, based on the nature of the process, the data collection methodology used, the sample size, outliers in the data etc. Few of the major Non-Normal distributions are listed below;
Can you use your code for z score?
The R code will work, but the z-score will be about as meaningful as the sentence “Grapes are phoning the fountain pen lightly.” It’s a valid sentence, but doesn’t convey anything meaningful. Judging by your R code, it seems like you think your data is Weibull distributed.