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9

This is a very subtle question and I encourage you to read the Wikipedia articles on these different subjects (t-test, chi-squared test, p-value, etc) because the authors worked hard to combat common misconceptions about these commonly used statistical tests. Here is a rather oversimplified rule-of-thumb for these different tests: t-test: Used when you are ...


5

My understanding of bootstrapping is that you may estimate variance (and thus standard error of the population mean) iff your measurements are independent and have the same population distribution, in which case a number of sampling-with-replacement calculations can be done. I suspect that this method of estimation would be less desirable with small n values ...


3

A good place to start would be Statistical Methods for Microarray Data Analysis. I'd also suggest papers from the labs of Terry Speed, Gary Churchill, John Quackenbush, and Gordon Smyth. Also, I found some papers that specifically reflect on your exact issue: how to apply the methods developed for DNA microarrays to analyze protein arrays. Eckel-Passow et ...


3

Usually if something is not expected to behave according to some scheme then the measured values for such a parameter are assumed to be normal. It is not just with gene expression but with all types of measurements like dimensions of an object, luminosity of an electric bulb, range of a bullet etc. In any measurement, the random error is modeled using ...


3

Additional Info T-test As A.Kennard said t-test is applied when the random variable is normally distributed. How to know what is normally distributed is a relevant question. Regular measures which suffer some random error of measurement are normally distributed. The mean values estimated from different samples (the experiment that generates that sample may ...


2

In your 5 points you basically cover several concepts of evolutionary biology. 1) The number of mutations depend on mutation rate. The mutation rate varies along genome sequences, species and individuals. According to the recent DECODE study (Kong et al., 2012) a human mother transmit on average 15 mutations to her offspring and a human father transmit on ...


2

I am not sure I'm answering your question but I hope this will help. There are two main models of genetic drift in biology: Moran model and Wright-Fisher model. The Wright-Fisher model implies picking $N$ beads (where $N$ is the population size) with replacement in order to form the new population. Therefore, the change in allele frequency (due to genetic ...


2

Define a "Hit" (based on some cutoff- evalue, score etc) Get output in the tabular format Count number of hits per query — it is usually given in the header; if you want to look for some selected hits (based on some cutoff, then you can parse the file and find out) Example file (header): # BLASTN 2.2.27+ # Query: TCONS_00036712 gene=XLOC_017996 # ...


1

Remi.b's answer is great, but here's something less technical if that's what you're looking for: Genetic mutations happen ALL THE TIME. Every time a cell divides, there is an error rate of about one per billion. That's a very low error rate per division, but when you multiply it by the number of divisions, times the number of cells, times the number of ...


1

I don't know about other groups, but about plants, number of families depends on the system you follow. Recent version of The Plant List (1.1) estimates about 352 000 species of Angiosperms and lists over 400 families. See http://www.theplantlist.org/1.1/browse/A/ It is very good and reliable source of information. Second very good source about plant ...


1

I can see why you might be confused! The authors chose bad notation, since the way they wrote it $w_i$ clearly depends not just on the choice of anenomefish species $i$ but also on the choice of anenome species $j$. And it is not clear how exactly they are performing their sum in the definition of SSR: sum over all possible anenome-anenomefish species pairs ...


1

I'm not a statistician, but I think the comments have got it right. There is never a reason to omit P values, statistical power or some other measure that you have done something that is not a random outcome. For the sake of reference lets define the terms you reference: Eta squared is a ratio of the variances of two sets of measurements Cohen's d is a ...


1

It has been associated with polymorphisms with the CD4 gene, which is usually implicated in type I diabetes. The wikipedia article for vitiligo also mentions studies for the NALP1 gene. NALP1 is expressed at high levels in T cells and Langerhan cells, white blood cells that are involved in skin autoimmunity.



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