Is it possible to include covariates in paired wilcoxon tests? (E.g., data from multiple test points (1 group), needing to account for 1 variable).
I just found https://cran.r-project.org/web/packages/MultNonParam/MultNonParam.pdf, I don't know if it is useful.
Related
I performed a clustering analysis of the media usage of different users in order to find different groups that use a specific set of media (e.g. group 1 use media A, B and C and group 2 use media B, C and D). Then I divided the datset in different groups, since the users belong to a specific group (as a consequence the original dataset and the new datasets have a different size). Within in this groups I like to cluster again which different media sets are used.
How can I determine the number of clusters to guarantee that the results are comparable?
Thank you in advance!
Don't rely on clustering to be stable.
It's a hypothesis generation tool.
You clustered, and now you have the hypothesis that there are groups ABCD of media usage. You should first evaluate if this hypothesis is adequate. Now what you want to do in your next step is to assign the labels to subsets of the data. First of all, you should be able to simply subset this from the previous labels. But if this really is different data, you can label new data, for example using the most similar record (nearest neighbor classification). But that is classification now, because your classes are fixed.
I have a huge list of bit vectors (BV) that I want to group in clusters.
The idea behind this clusters is to be able to choose later BVs from each cluster and combine them for generate a BV with (almost) all-ones (which must be maximized).
For example, imagine the 1 means an app is Up and 0 is down in node X in a specific moment in time. We want to find the min list of nodes for having the app Up:
App BV for node X in cluster 1: 1 0 0 1 0 0
App BV for node Y in cluster 2: 0 1 1 0 1 0
Combined BV for App (X+Y): 1 1 1 1 1 0
I have been checking the different cluster algorithms but I did found one that takes into account this "complemental" behavior because in this case each column of the BV is not referred to a feature (only means up or down in an specific timeframe).
Regarding other algorithms like k-means or hierarchical clustering, I do not have clear if I can include in the clustering algorithm this consideration for the later grouping.
Finally, I am using the hamming distance to determine the intra-cluster and the inter-cluster distances given that it seems to be the most appropiated metric for binary data but results show me that clusters are not closely grouped and separated among them so I wonder if I am applying the most suitable group/approximation method or even if I should filter the input data previously grouping.
Any clue or idea regarding grouping/clustering method or filtering data is welcomed.
This does not at all sound like a clustering problem.
None of these algorithms will help you.
Instead, I would rather call this a match making algorithm. But I'd assume it is at least NP-hard (it resembles set cover) to find the true optimum, so you'll need to come up with a fast approximation. Best something specific to your use case.
Also you haven't specified (you wrote + but that likely isn't what you want) how to combine two 1s. Is it xor or or? Nor if it is possible to combine more than two, and what the cost is when doing so. A strategy would be to find the nearest neighbor of the inverse bitvector for each and always combine the best pair.
New with Matlab.
When I try to load my own date using the NN pattern recognition app window, I can load the source data, but not the target (it is never on the drop down list). Both source and target are in the same directory. Source is 5000 observations with 400 vars per observation and target can take on 10 different values (recognizing digits). Any Ideas?
Before you do anything with your own data you might want to try out the example data sets available in the toolbox. That should make many problems easier to find later on because they definitely work, so you can see what's wrong with your code.
Regarding your actual question: Without more details, e.g. what your matrices contain and what their dimensions are, it's hard to help you. In your case some of the problems mentioned here might be similar to yours:
http://www.mathworks.com/matlabcentral/answers/17531-problem-with-targets-in-nprtool
From what I understand about nprtool your targets have to consist of a matrix with only one 1 (for the correct class) in either row or column (depending on the input matrix), so make sure that's the case.
I have a question about the chi-square test.
I have two between-subject factors, each with two levels (so 4 conditions). Furthermore, I have one dependent variable (qualitative), also consisting of two levels.
Now I want to make pairwise comparisons (so I have 6 chi-sqaure test in total). Is there any way I can control type-1-errors? In the literature I saw they often calculated interaction with a chi-sqaure test. Is this the way to do it, and if so, how do I do it?
I can work with both SPSS and Matlab.
Thank in advance!
Niels
I have thousands to ten-thousands of data points (x,y)coming from 5 to 6 different source. I need to uniquely group them based on certain distance criteria in such a way that the formed group should exactly contain only one input from each source and each of them in the group should be within certain distance d. The groups formed should be the best possible match.
Is this a combination of clustering and nearest neighbor?
What are the recommendation for the algorithms?
Are there any open source available for it?
I see many references saying KD tree implementation and k-clustering etc. I am not sure how can I tailor to this specific need.