Linked Questions

1 vote
0 answers
716 views

Why according to distribution graph it's normally distributed, but Jarque-Bera test shows non-normally distributed? [duplicate]

I am working on Kaggle's house pricing exercise and I cannot understand something. I watch and read articles on normality tests, and more specifically JB test, but I cannot understand why according to ...
Georgi's user avatar
  • 11
375 votes
15 answers
147k views

Is normality testing 'essentially useless'?

A former colleague once argued to me as follows: We usually apply normality tests to the results of processes that, under the null, generate random variables that are only asymptotically or ...
shabbychef's user avatar
  • 14.7k
138 votes
3 answers
50k views

What if residuals are normally distributed, but y is not?

I've got a weird question. Assume that you have a small sample where the dependent variable that you're going to analyze with a simple linear model is highly left skewed. Thus you assume that $u$ is ...
MarkDollar's user avatar
  • 5,885
24 votes
7 answers
19k views

Appropriate normality tests for small samples

So far, I've been using the Shapiro-Wilk statistic in order to test normality assumptions in small samples. Could you please recommend another technique?
aL3xa's user avatar
  • 2,181
50 votes
5 answers
39k views

Normality of dependent variable = normality of residuals?

This issue seems to rear its ugly head all the time, and I'm trying to decapitate it for my own understanding of statistics (and sanity!). The assumptions of general linear models (t-test, ANOVA, ...
DeanP's user avatar
  • 871
10 votes
2 answers
5k views

Goodness of fit to Poisson Distribution

What are some of the well known statistical tests to measure goodness of fit of observed random variables to a poisson distribution? I know the Kolmogorov-Smirnov test is one such, are there any ...
user avatar
9 votes
2 answers
5k views

Non-normality in residuals

I refer to this post which seems to question the importance of the normal distribution of the residuals, arguing that this together with heteroskedasticity could potentially be avoided by using ...
Cesare Camestre's user avatar
6 votes
1 answer
4k views

Can one measure the degree of empirical data being Gaussian?

I would like to inquire about a simple test I might be able to perform to determine how 'nicely Gaussian' my empirical data are. If they are 'nicely Gaussian', then I can perform some other analysis, ...
Creatron's user avatar
  • 1,645
5 votes
2 answers
13k views

How to get the expected counts when computing a chi-squared test?

I just have 1500 data points in excel. However, I want to do a chi squared test to prove if the data is normaly distributed. My question is: How to calculate the expected range for such a large data ...
Le Max's user avatar
  • 3,719
11 votes
1 answer
8k views

I log transformed my dependent variable, can I use GLM normal distribution with LOG link function?

I have a question concerning Generalized Linear Models (GLM).My dependent variable (DV) is continuous and not normal. So I log transformed it (still not normal but improved it). I want to relate the ...
Scientist's user avatar
  • 155
1 vote
2 answers
19k views

What to do when Kolmogorov-Smirnov test is significant for residuals of parametric test but skewness and kurtosis look normal?

I have conducted a parametric test in a study, n=290. I want to assess whether the residuals of this test are normally distributed. The skewness and kurtosis of the residuals are -0.017 and -0.438 ...
user25551's user avatar
2 votes
2 answers
17k views

Tests for lognormal distribution

I have some data in the following manner. 10 3 4 5 6 9 ... I have to check that the difference between returns is log normal by doing ln(return/previous return). I know some tests for normality if i ...
Jim's user avatar
  • 21
6 votes
1 answer
7k views

Appropriateness of K-S test and Kruskal-Wallis for assessing medical data set

I am analyzing some stats for a paper I am writing. I have statistics help available through my faculty but am not there for a couple of months so hoping you can help out. n = 463, 2 patient groups( &...
rob123's user avatar
  • 163
8 votes
1 answer
864 views

Kolmogorov Smirnov conflicts with visual data

I recorded the length of 197 nursing care episodes. My normalised data $(x-\mu)/\sigma$ looks like this: Kolmogorov-Smirnov gives me a p-value of 0.14. Can't be right surely?! Am I misinterpreting my ...
HCAI's user avatar
  • 779
3 votes
1 answer
8k views

Can non normal data be used for factor analysis and multiple regression? If so what is the procedure to justify it?

While I was writing up the analysis in my thesis, I just came across when rechecking my test for normality, that the p-value for most continuous variables was .000, which is less than .05, and it ...
Arosha's user avatar
  • 31

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