21 votes
Accepted

How statistically significant was the "sweaty T-shirt" experiment?

First, let's consider the original Wedekind et al (1995) study. Sample sizes seem reasonable, if the effect is not very noisy: [...] 49 female students (average age: 25.2 years, s.d. = ­4.0) and ...
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  • 3,294
19 votes

Is it scientifically sound to pool repeated measurements?

If you use the configuration on the left, your variance across tubes reflects variance between individuals. If you use the configuration on the right, your variance across tubes reflects primarily ...
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11 votes
Accepted

Do biological phenomena follow Gaussian statistics?

kmm's answer is correct; I just want to add some of my points on what kind of data should follow Gaussian distribution. Unless you know from observation that a process doesn't follow a Gaussian ...
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10 votes

What are the odds of being an albino human and have Down syndrome?

It is correct if (and only if) albinism and Down syndrome are independent events, that is, if albino people is not more nor less likely to have Down syndrome than non albino people (and vice-versa). ...
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  • 586
9 votes

What is the difference between a mechanistic and a statistical predictive model?

Mechanistic model answers the how question. These models are usually biophysically detailed, and designed to be causal. Say you discovered a linear relation between blood pressure drug and heart rate. ...
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  • 3,045
9 votes

Do biological phenomena follow Gaussian statistics?

You raise two issues, both of which might be better suited for stats.SE, but I think the questions are suitably biological to warrant an answer here. Do most biological processes follow a Gaussian ...
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  • 12.1k
8 votes

How many (taxonomic) families are there?

The NCBI Taxonomy statistics page displays the following information: There are currently 73540 genera, 331418 species, and 23127 taxa of higher order. Since the number of taxa decreases with the ...
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  • 9,314
8 votes
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Where are the statistics for vaccine side effects?

(World Health Organisation, 2014. p. 2) shows the adverse effect (side-effect) rates for the MMR vaccine. For instance, fever between the 7th to 12th day after vaccination occurs in 5 to 15% of ...
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  • 1,495
7 votes
Accepted

What is the optimum length of abstinence for maximum ejaculation volume in humans?

There don't appear to be many robust studies on this, but this study by De Longe et al in 2004 suggests that, whilst the volume of the ejaculate is increased after 5-days of abstinence (in most ...
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  • 6,169
7 votes

Is there a statistical analysis test I can perform that will give me a estimate of total population from my own smaller data sets?

I'm assuming you're asking how to estimate population size based on numbers of individuals you capture. Yes, there are many approaches to this. The R library SPECIES-R offers a number of methods of ...
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  • 14.1k
7 votes
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Which statistical test should be used for GC-content comparison?

You could try a permutation test. These are a kind of non-parametric statistical test which involve creating your own null distribution from your data. Your hypothesis $H_{1}$ in this case, is that ...
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  • 2,053
6 votes
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How should species density be calculated for a clumped distribution?

To me, there are two issues that are mixed up here (if I understand you correctly). First, do you want to estimate the mean and variance for a statistical population (i.e. to characterize a larger ...
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6 votes

How many (taxonomic) families are there?

The Plant List has 642 families listed: http://www.theplantlist.org/1.1/about/#changes. For a quick comparison, Wikipedia lists 522 fish families: en.wikipedia.org/wiki/List_of_fish_families 136 ...
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6 votes
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How many (taxonomic) families are there?

The 2011 paper How Many Species Are There on Earth and in the Ocean? indirectly answers this question as well as any other source you'll find I imagine. It estimates how many species there are total ...
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  • 3,180
6 votes

How statistically significant was the "sweaty T-shirt" experiment?

@bshane has already provided an excellent answer to the question. However, I just found a recent review published in Molecular Ecology (Winternitz et al., 2016) in which the authors performed a ...
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  • 2,878
6 votes
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Why Poisson Process for neural firing?

You can read about the differences between a binomial and poisson distribution at this other question on Math.SE. First, since spikes are discrete events, it makes most sense to use a probability ...
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  • 36.6k
6 votes

Why isn't life expectancy normally distributed?

The histogram you show isn't a distribution of age-at-death for individuals, it's a distribution of life expectancies for different countries. The post you link takes data from a table on the ...
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  • 7,729
6 votes
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What is the best method to check for differential gene expression in large dataset? I want to identify aging differentially expressed genes

A standard pipeline for DGE would be Salmon for (pseudo)mapping + DESeq2 for statistical analysis. Salmon is one of a set of modern, fast and accurate mapping software. Requires a transcriptome to be ...
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  • 224
5 votes
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Bayes theorem for mutations

I don't understand your calculations and I don't understand why you're trying to use Bayes formula. I don't know the $\frac{1-p}{2-p}$ formula and I don't understand what it is supposed to calculate. ...
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5 votes
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Biostatistics: Pollen dispersal directionality

(This isn't an answer, but hopefully it will help get it past the experimental design into just solving the equation.) Where did you get that α0 was not determined from their data? On p. 10 (256), ...
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  • 161
5 votes
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What are the odds of being an albino human and have Down syndrome?

Probability of independent events Assuming the albinism and Down syndrome are independent traits, then the probability of having both traits is the product of the probability of having each trait. ...
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  • 67.6k
5 votes
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Don't understand figures in this citizen-science mosquito ID project

In the second figure – What does the color scale and color coding represent? Each color is an individual mosquito species, arranged the same from top to bottom on all plots. Here, on the ...
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  • 181
5 votes
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Book about ordination in ecology

I took a class in ordination methods a few months ago and found the following books helpful in better understanding the various techniques: Multivariate Statistical Methods: A Primer by Brian Manley ...
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5 votes
Accepted

Why do coronavirus cases graphs have a sinusoidal like shape?

It's a weekly cycle due to reporting disruptions over the weekend. Use a 7-day moving average to get a better picture. Holidays and such can still be disruptive but the 7-day average solves most of it....
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4 votes
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Why estimate linear and full (linear, quadratic, and correlational) selection coefficients separately?

This is directly following the advice of Lande & Arnold (1983), saying: Linear multiple regression can be used first to estimate the forces of directional selection, $\beta$, and their ...
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4 votes
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Data Bias in protein-protein interactions data

I'm one of the STRING maintainers, so I hope I can clear things up a bit. Gene co-occurrence: genomic context methods are very useful for bacterial genomes, but not so much for eukaryotes. However, ...
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  • 4,070
4 votes

What are the benefits of statins in terms of prolonging life?

I suspect I won't be crunching as much numbers as you'd want me to, however here are some basic points: Statins have shown a clear ability to improve the blood llipid profile. Their use in primary/...
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  • 1,402
4 votes

Do biological phenomena follow Gaussian statistics?

You are right to be suspicious. I would contend that, in most situations, hypothesis tests based on the normal distribution are not appropriate. If hypothesis testing is needed, a permutation test ...
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  • 5,595
4 votes
Accepted

Why does drinking milk lead to increased fractures?

The authors suggest a reason in their abstract: Given the observational study designs with the inherent possibility of residual confounding and reverse causation phenomena, a cautious ...
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  • 12.1k
4 votes
Accepted

Confusion about read counts distribution in RNA-seq

Textbook example of multinomial distribution is multiple dice toss. The fair dice has following probabilities: ...
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