normal-distribution

  1. J

    Normality requirements for One-Way ANOVA, SPSS vs SigmaPlot

    Hi, I’m a bit confused about the requirements for normality using a One-Way ANOVA. I had always thought that in order to use a One-Way ANOVA, 2 requirements had to be met: 1 - The data should be normally distributed for each category of the independent variable. That is, say I had 3...
  2. B

    Shapiro-Wilks significant, all other indicators NORMAL

    Hello everyone, I am checking my assumptions before running an ANCOVA, one of which is that the DV is normally distributed across all levels of the IV. MY IV is 3 groups (Ns of 32, 31, and 32) and my DV is a continuous variable from 1 - 5. Before splitting into groups, it looks normal and the...
  3. C

    Calculating the amount of underestimation

    Coverage rate for a parameter is 91.2%, and the nominal coverage rate is 95%. If the confidence interval is based on asymptotic standard normal, then the amount of coverage 91.2% implies that the standard errors for the parameter is estimated about 15% too small. Because z* value used to make a...
  4. A

    Crises: ANOVA? How to analyse non-normal, non-Homogeneity data with different N group

    Dear all, I'm somewhat new the world of statistics, or at least it has been years since I last used it and basically the only program I know generally how to work with is SPSS. However, for my Master thesis I need to analyse a dataset I made, so there's no escaping it now. My research is...
  5. T

    Interpretation of a Q-Q plot and Shapiro-Wilk test

    I have the following output from a shapiro-wilk test: Shapiro-Wilk normality test data: goalTime W = 0.9486, p-value = 0.05751 And the Q-Q plot below: http://i.stack.imgur.com/AGd8u.png Would it be safe to say I cant reject the null hypothesis that the data is normal? What would be the...