1. Z

    The effects of transforming skewed data

    Hi There, I would like to know more about transforming data. I know that for parametric statistics data needs to be normally distributed, but I am confused about when this does and does not apply. Doesn't transforming data to make it normally distributed hide any experimental effects you...
  2. W

    mean+standard deviation+skewness+kurtosis

    hi I want to order some variables according to (mean+standard deviation+skewness+kurtosis) or some new rule considering mean value, standard deviation, skewness and kurtosis simultaneously. Is there any similar sorting rule like this? Is this equation used in other research ares? thank you.
  3. D

    Excel formula for the inverse Pearson IV distribution?

    Hello Everyone, What is the excel formula to generate the inverse Pearson IV distribution? I have mean, standard deviation, skew and kurtosis and I plan to generate random outputs given those stats. How do I write the formula? My question is very direct and simple. I've looked everywhere...
  4. B

    Different variables - most normally distributed, a couple are not - best test to use?

    Hello everyone So glad I've found this site and hope that someone will be able to point in the right direction! I am looking at how physical activity scores (mins per week) in children, change pre and post intervention - as part of this I want to see what the affect of parental involvement...
  5. J

    Using a kurtosis statistic as a dependent variable

    Hi everyone, I am working on a research project in public policy and I am testing kurtosis for on the year-to-year budget changes (as %) in different policy areas. In the literature we know there will more than likely be L-kurtosis so I want to take it one step further. I would like to...
  6. C

    Normality tests and Shape statistics contradictory

    Hello. I am testing for normality on a number of repeated measures variables in a sample of 29 people. Both the Kolmogorov-Smirnov test and the Shapiro-Wilk test statistics say that all of these variables are significantly non-normal. However, observations of skew and kurtosis (as well as...
  7. D

    Comparing skewness and kurtosis of two distributions

    Hi, Until now, I knew that if skewness=0 and kurtosis=3 it means the distribution is as symmetric/as tall as the normal distribution. But in SPSS you have to compare it with 2xStandard error and if it is smaller it means that there is no asymmetry and kurtosis. Now, my question is, how can I...
  8. P

    Error on the standard deviation, skewness & Kurtosis

    Dear all, Given a sample of N points extracted from a distribution, I would like to know how to estimate the error on the higher moments of the distribution, such as the standard deviation, the skewness and kurtosis. In other words, I know the error on the mean is simply sigma/sqrt(n), but...
  9. J

    Estimating values from kurtosis and skewness

    If I know the size of a population, the number of categories/labels, and the skewness and kurtosis of the distribution, is it possible to estimate the number of items which fall into each category? For example, given the data set: category A: 11 category B: 13 category C: 15 category D...
  10. S

    Finding z score of skewness and Kurtosis

    Dear all, I'm studying stat from Andy Field's "DISCOVERING STATISTICS USING SPSS" 3rd ed. In chapter 5 (Exploring assumptions) page 138 the writer said "To transform any score to a z-score you simply subtract the mean of the distribution (in this case zero) and then divide by the standard...