Is there a (dis-)advantage in dicotomizing Likert data?

Given there is some k-step (k=3 or 5 or 7 etc) Likert data with "absolutely no" on one side, "absolutely yes" on the other side, and "neutral" in the middle. A correct way to analyze such...

07 August 2020 1,107 5 View

Is it correct to call lo(w)ess "non-parametric"?

It's a weighted least-squares polynomial regression, so it's based on assuming normal errors, and the normal probability model is parametric. However, in some statistics book and online statistics...

28 October 2018 2,985 6 View

Patlak slopes from dynamic PET data with delayed begin of acquisition?

I'm currently working with pesudo-dynamic PET scans, i.e. data containing sequentially acquired time frames. Using all the time frames I can 'easily' compute the Ki-values (slopes of the...

11 August 2016 4,566 1 View

Best / easiest software to use for qualitative research (Grounded Theory)?

What is the best / easiest software to use for qualitative research (Grounded Theory) for a rather small data set (seven 1hr interviews) for a beginning researcher? I am looking for a particular...

12 April 2016 4,908 24 View

Are these models equivalent?

27 January 2016 410 7 View

How to calculate the sample size (t-test) when additional data is available to estimate the standard error?

Consider following case: There are k different groups, but only the mean difference between 2 of these groups should be tested (t-test, consider the assumptions are met and alpha and beta are...

14 October 2015 7,922 11 View

Electrostatic adhesion manufacturers?

Can anyone provide manufacturer details for electrostatic adhesion components as used by climbing robots for example?

18 September 2014 2,174 3 View

Could optogenetics provide a new interface between electronics and biological nervous systems?

The control of robotic prosthesis via signals from the nervous system has reached an impressive level in recent years. However, the feedback of signals from the prosthesis back into the nervous...

18 May 2014 8,935 7 View

Least-squares only for normal distributed errors - can anyone help?

A parameter of a statistical model should be estimated from iid data. For simplicity, let's consider a single-parameter model. The likelihood principle sais that the best estimate for the...

18 March 2014 4,717 56 View

Anyone want to collaborate on a data base for animated organic chemical reaction mechanisms?

I started to develop a data base with gif-files of organic reaction mechanisms. Are there any other colleagues who are working in this field and want to...

28 January 2014 8,121 2 View

How to compare two groups with only two measurements?

Hiiiii everyone! I have an enquiry on statistical analysis. I was looking for many forum and it's still cannot solve my problem. I want to compare means of two groups of data but only with two...

03 March 2021 8,796 3 View

Can we classify HV and LV lines based on line length?

I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on...

03 March 2021 4,116 4 View

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10?

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10? Since, the growth curve from day 2 to 10 won't be like the "Logistic curve" it might not follow logistic...

03 March 2021 1,401 3 View

What test should I use to compare two or three means, if data is not normally distributed but sample size is > 30 in each group?

I personally feel this as a most confusing question. As per my understanding, if sample size is > 30, and sample is skewed, we can still use paramteric approach, as it will follow Z...

01 March 2021 1,587 6 View

Distribution of particles in metal matrix?

How would define the "good" and "poor" distribution of particles within the matrix. Is there a quantitative solution to assess the distribution of the particles, which then having denotation of...

28 February 2021 7,397 8 View

Is there a deep reason for using the squared modulus of the wave function as the probability density of the existence of the particle?

I think we were all surprised at the first time we got to know quantum mechanics that the squared modulus of the wave function is the probability density of the existence of the particle? The role...

28 February 2021 6,282 9 View

How to find the right number of integration points in second order 3d finite elements?

I am familiar with finite element simulations and numerical schemes like the Gauss Legendre quadrature. I also know that the Gauss integration yields exact values for polynomials up to degree 2n-1...

27 February 2021 6,818 3 View

VIF very high, but correlation is low and coefficient is significant. Which one whould I choose?

Hello. I have a question whether if my coefficients (statistically significant) would be valid when VIFs are really high. In my model, there are independent variables(IV), moderating variables...

26 February 2021 956 13 View

How to plot the probability paper of Gumbel distribution using R programing?

In R-studio, there are many commands of Gumbel package. Arguments are also different. I`m asking about the alpha parameter of the Copula which must be greater than 1. If this is the one used to...

25 February 2021 5,229 3 View

Data Analysis K-S and S-W tests?

Hello, I have conducted analysis where the K-W and S-W have come out as p

25 February 2021 9,648 3 View