10k views

### What misused statistical terms are worth correcting?

Statistics is everywhere; common usage of statistical terms is, however, often unclear. The terms probability and odds are used interchangeable in lay English despite their well-defined and different ...
14k views

### Which has the heavier tail, lognormal or gamma?

(This is based on a question that just came to me via email; I've added some context from a previous brief conversation with the same person.) Last year I was told that the gamma distribution is ...
3k views

### Can somebody offer an example of a unimodal distribution which has a skewness of zero but which is not symmetrical?

In May 2010 Wikipedia user Mcorazao added a sentence to the skewness article that "A zero value indicates that the values are relatively evenly distributed on both sides of the mean, typically but not ...
10k views

### How is the kurtosis of a distribution related to the geometry of the density function?

The kurtosis is to measure the peakedness and flatness of a distribution. The density function of the distribution, if it exists, can be viewed as a curve, and has geometric features (such as ...
583 views

### Kurtosis of made up distribution

Take a look at the image below. Blue line indicates standard normal pdf. The red zone is supposed to be equal to the sum of grey areas (sorry for awful drawing). I wonder can we create a new ...
1k views

### Skewness, kurtosis and how many standard deviations values are from the mean

As is well known for the normal distribution, 68% of the probability mass is within one standard deviation of the mean, 95% within two standard deviations and 99.7% within 3 standard deviations. ...
614 views

### Testing for normality in non-normal distributions with zero skewness and zero excess kurtosis

[This question was formerly called "On Non-normal distributions with zero skewness and zero excess kurtosis" and relabeled to better reflect its focus.] I am trying to write a little simulation using ...
617 views

### Question about Normality of 5-point Likert scale

I'm really having a hard time trying to normalize my data. My study is about green IT product acceptance. There are eight factors, six are 5-point Likert scale (Str.disagree - Str.agree), one is 2-...
715 views

### Similarity measures between bimodal distributions

I have to compare two bimodal distributions. So far, I have found the Bimodality Coefficient: $$BC = \frac{\mu_{3}^{2} + 1}{\mu_{4} + 3\frac{(n-1)^2}{(n-2)(n-3)}},$$ with $\mu_{3}$ referring to ...