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16
votes
1answer
636 views

Additive genetic variance components from LMER in R

I've set up some dummy data in R which makes 40 genetically related lines, they are all siblings within a line so are genetically related by a factor of ½ thus additive genetic variance should be ...
11
votes
1answer
135 views

Biostatistics: Pollen dispersal directionality

What Information am I looking for? Think about a tree that is sending pollen all over the place. Because of wind, most pollen grain will go toward one direction. Imagine, we split the 2D area around ...
9
votes
3answers
25k views

Deciding between chi square and t test

I am always so confused whether to do a chi square test or a t test in the sums given by my biostats teacher. Does anyone have a simple rule to decide this?
9
votes
1answer
125 views

Is bootstrapping an acceptable way to determine standard error for binding constants? [closed]

I'm measuring binding constants my system and I appreciate the usual methods of using replicates to measure standard errors and using those errors to calculate propagation of error. I'm curious if ...
7
votes
3answers
1k views

How many (taxonomic) families are there?

Approximately, how many families have been identified? I've often often come across figures for the total number of species on Earth. Recently, I found myself wondering about the encompassing ranks ...
5
votes
1answer
280 views

Are descriptive statistics sometimes more useful than tests of significance?

How does the biology community currently feel with regards to publishing descriptive and effect size statistics rather than significance stats? Almost every journal article I read in the cell biology ...
4
votes
1answer
119 views

Is there a correlation between incidence of type 1 diabetes and vitiligo?

Does the data indicate that if you have one, the probability of you having the other is higher than that of someone who doesn't have the one?
4
votes
1answer
87 views

The dominance variance on a single locus

I was reading the book "Genetics and Analysis of Quantitative Traits", by Lynch and Walsh. I how the covariance between two individuals with IBD $\Theta$ gets divided into just the additive variance ...
3
votes
1answer
68 views

What does the Gini index mean in a biochemical context?

What is the meaning of the Gini index, as specificed in this link, which describes the Gini index of beta-glucopyranose bound to hexokinase? Is this true that if Gini index has a very low value that ...
3
votes
2answers
140 views

Choosing appropriate statistical test for ordinal data

Ordinal response variables show up often in biology, but I'm not sure how they are best analysed. Some examples are qualitative assessments (little, many, a lot) or risk assessments (low risk, medium ...
3
votes
1answer
49 views

Why genes are assumed to follow multivariate normal?

I wonder why gene expression data are very frequently modeled by multivariate normal distributions. What is the reason for those strong assumptions that the genes follow multivariate gaussian? Are ...
3
votes
0answers
66 views

Is there a standard formula/calculation for sexual dimorphism?

Is there a standard, or most accepted, way to present a value for sexual dimorphism? For example, one could use $$\frac{\text{Female value}}{\text{Male value}} -1$$ This would give negative values ...
2
votes
2answers
256 views

On evolution statistics [closed]

This basic evolution theory question has been haunting me since childhood and I'm kind of embarrassed that I can't explain it yet: Consider a butterfly. It's wings have evolved to look like the eyes ...
2
votes
1answer
40 views

Material on the analysis of (micro)array data

I'm at the moment analyzing cytokine array data. The available material on the statistical analysis of these data is more than unsatisfactory. Since a lot of effort is being made in the analysis of ...
2
votes
2answers
131 views

Local BLAST Copy Number per Hit

I generated a series of local BLAST databases using makeblastdb of metagenomic data and am searching for the presence of a particular gene. While I can do the normal BLAST analysis looking at ...
2
votes
1answer
15 views

When performing mutagenesis for an assay, how do you decide on the sample size of individuals to be mutated such that all genes are covered?

If I want to study, say, gustatory response of salmons to a bile acid, I need to mutagenize a sample of salmon males. However, given that there are many genes involved in this response, what is ...
2
votes
1answer
101 views

Niche overlap Index

I wanted to use the compana() function from the adehabitat package in R. I don't really understand the meaning of the data in ...
1
vote
1answer
80 views

Bootstrap question

I have a question about bootstrapping: The way that I understand it is that each number represents how well a given node is supported. So in the diagram presented, we can see that the ...
1
vote
1answer
89 views

Multi-modal distribution for gene expression data

Why would some genes have more than two modes in their expression distribution? What external factors would cause this anomaly? I'm referring to the expression distribution of a gene across different ...
1
vote
1answer
69 views

Needing help in order to infer the statistical hypothesis tests performed in an old paper

I am in great need of help in order to infer the statistical hypothesis tests performed in an old paper. However I need to make some reasonable guesses only from the abstract of the paper since the ...
1
vote
1answer
185 views

Standardized Selection Ratio (SSR)

In this article the athors used the Standardized Selection Ratio (SSR) in order to infer what is the preferred host (anemone) of anemonefish. Here is a quotation coming from their methods: ...
1
vote
0answers
33 views

Quantifying temporal-spatial data [closed]

Imagine a set of territories each subdivided into 5m grid cells. Each grid cell represents a spatial unit, and that unit can have any number of variables associated with it - e.g. habitat ...
0
votes
1answer
103 views

Normalised gene counts to edgeR/DESeq2?

Both very popular differential expression packages assume a raw gene matrix count. This makes sense because the statistical model models the library depth. But what if I normalize my counts with say, ...
0
votes
1answer
179 views

Gene pool simulation [closed]

this simulation, you sampled the gene pool without replaceing beads in the beakerafter you drew each one. Thus, f(A) and f(a) in the gene pool changed slightly after each bead was drawn. For example, ...
0
votes
0answers
28 views

Large set of semen microscope images needed

As a course project I have to write an algorithm whose purpose is to analyze a sperm sample (total number, motility etc). In order to do that though, I need to have a sufficient number of images to ...