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18 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 ...
Bryan Krause's user avatar
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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). ...
Pere's user avatar
  • 586
8 votes
Accepted

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 ...
Jam's user avatar
  • 1,506
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 ...
iayork's user avatar
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7 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....
Bryan Krause's user avatar
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7 votes
Accepted

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 ...
user438383's user avatar
  • 2,351
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 ...
AlexDeLarge's user avatar
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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 ...
Oosaka's user avatar
  • 3,253
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 ...
Bryan Krause's user avatar
  • 46.1k
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 ...
acvill's user avatar
  • 8,296
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 ...
Greg's user avatar
  • 224
6 votes

Statistical significance set at $p < 0.05$ or $\alpha = 0.05$?

Definitely α; α is the threshold you set, p is the probability you measure, you compare p to α. If α = 0.05, then you consider p < 0.05 significant. See e.g. https://en.m.wikipedia.org/wiki/P-value ...
Bryan Krause's user avatar
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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. ...
Remi.b's user avatar
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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 ...
lauir's user avatar
  • 181
5 votes
Accepted

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 ...
Jenny Hansen's user avatar
5 votes

Is Eugene Koonin's probabilistic argument for the necessity of a multiverse to explain the origin of life sound?

There are two main problems here: The logic assumes that a complete, simplified ribosome is the simplest possible useful unit, so has to spring up by a series of random events. This is extremely ...
lupe's user avatar
  • 203
5 votes
Accepted

Hypothetical violation of independence assumption for linear models

Observations are assumed to be independent, not predictors. For example, if you were doing some chemical fertilizer treatment, you'd probably not apply a random chemical or random dose of chemical to ...
Bryan Krause's user avatar
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5 votes
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How to correctly assess the impact of invasive species on a community using the diversity index?

My best recommendation would be to consider what each measure is actually telling you, and only using that measure for an appropriate question. Abundance and diversity are different things. As you ...
Darlingtonia's user avatar
  • 2,659
4 votes
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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 ...
kmm's user avatar
  • 12.3k
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: ...
BagiM's user avatar
  • 583
4 votes
Accepted

Are sizes of potatoes normally distributed?

According to Evaluation of the Effect of Density on Potato Yield and Tuber Size Distribution potato tuber size was estimated using a normal distribution but they are not normally distributed They ...
Hachiloni's user avatar
  • 983
4 votes

Is the coronavirus getting less dangerous?

The issue is using the number of positive tests as a measure for the total number of active cases at a given time. At least in the U.K., the early testing capacity was much lower than it was now: ...
user438383's user avatar
  • 2,351
4 votes

Beta-diversity for data with zeros

I would recommend using a Bray-Curtis dissimilarity matrix since it accounts for abundances and can handle the so called double zero problem. I'm on my commute now and so must return to this for a ...
theforestecologist's user avatar
4 votes
Accepted

How much does dry moose scat weigh and vary in dry weight?

MacCracken and Van Ballenberge, 1987 report that pellet size varies a bit by sex and age; male pellet dry weight (all measurements are dry) averaged 1.9 grams (range 0.9-2.9), female 1.3 g (range 0.6-...
Bryan Krause's user avatar
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3 votes
Accepted

How correlated are the lengths of tendons in different part of a human body?

I couldn't find studies analysing clearly enough tendons size, but a couple of sources show that they are probably correlated: One study found correlation between dimensions of Achilles'tendon and ...
Pere's user avatar
  • 586
3 votes

How to assess if biological measurements follow a normal or a log-normal distribution

Preprocessing will and should always depend upon the biology that you try to answer or discover (e.g.: There might be an experimental rationale to believe that some genes behave differently in ...
tsttst's user avatar
  • 1,597
3 votes
Accepted

How to assess if biological measurements follow a normal or a log-normal distribution

From personal experience, nearly all count data whether from microarray or reads from RNAseq of some kind, requires a log transformation of the counts. Usually a small fraction is added to all values ...
akaDrHouse's user avatar
  • 1,309
3 votes

Log-tranformation and GWAS

Yes, use the log-transformed phenotype. if you want to use a normally distributed error term, and this will only occur if the phenotype is log-transformed, then you must log-transform the phenotype. ...
user42909's user avatar
  • 535
3 votes

Book about ordination in ecology

You might also want to consider: Tree diversity analysis by Kindt and Coe 2005. Freely and legally available here. Not very deep but nice and crisp introductions + its free. Numerical Ecology with R ...
JonJup's user avatar
  • 31
3 votes
Accepted

Why isn't life expectancy normally distributed?

There's no particular reason everything in nature needs to fit a normal distribution; normal distributions are just one of many different types of naturally-occurring distributions. In some cases, the ...
iayork's user avatar
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