The study of the collection, analysis, and interpretation of data.

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9 views

Repeating assays assessing drug synergy by Chou and Talalay method

I have been using MTT cell viability assays to test compounds, both as single agents and in combination, in a constant ratio. From these assays I have been able to plot the median effect plot to get ...
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1answer
14 views

Statistical genetics: Allele frequencies that follow a Dirichlet distribution

From Foll and Gagiotti (2008) (software BayeScan). They consider a model where several subpopulation are derived from a unique ancestral population. We consider a set of $I$ loci and let $K_i$ be ...
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1answer
33 views

Given the number of individuals who have a recessive disorder, how can one calculate the probability that the disorder was inherited? [on hold]

Just to be clear, this is not homework. Suppose a biological family has five children, two of whom have a certain recessive genetic disorder that is not sex-linked. The parents themselves do not have ...
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0answers
33 views

How to estimate heritability from breeding data

I have a lot of plant-breeding data (tens of thousands of results) that are composed of phenotypes of parents and offspring. The plants however went trough years of selection and it is not balanced. ...
2
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0answers
35 views

Estimated protein size using CDs data [closed]

The number of amino acids in a protein is important to predict their size. I used coding DNA sequence (CDs) to predict the average of the protein size of E.coli k12 from a sample provided by the ...
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0answers
44 views

How can I calculate Shannon-Wiener diversity index in caves with different kind of habitats and different sampling methods?

I would like to start a monitoring in different caves, compare caves of different age and length, and find out if there are any correlations between these factors and their diversity. I was thinking ...
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1answer
31 views

Get Parent GO terms of GO term vector?

I have a vector of GOIDs that are specific GO IDs outputted from an enrichment analysis. I want to cluster my GOIDs by their parent GOID term. I used GOstats to do my enrichment analysis, and I have ...
3
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2answers
49 views

Different Effects of Detection Probability Between Presence and Count Data at the Same Location

I'm modeling habitat suitability for a large, mobile animal using occurrence data (presence only - I have no true absence data in this case) collected from camera traps (stations with automatic ...
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0answers
16 views

What is the best test for SNV clustering?

I am looking for a method to cluster single nucleotide polymorphisms based on clinicopathologic data (mainly receptor immunoistochemistry). So far, I've came up with only two that handle dummy ...
5
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1answer
39 views

Is “aggregate percentage” still a valid term in ecology?

Martin et al. 1946 define "aggregate percentage" as a metric that describes the mean percentage contribution of a group to the total mass/abundance of all samples. The metric is useful in datasets ...
3
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1answer
76 views

Distinguishing Father from Brother

Given the (non-identical) DNA sequences of two men and the knowledge that the second man is either the father, brother, or son of the first man, is the DNA useful in determining which of these three ...
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0answers
39 views

How should one interpret heritability? Is it related to $R^2$?

From Wiki: Heritability estimates are often misinterpreted if it is not understood that they refer to the proportion of variation between individuals on a trait that is due to genetic factors. It ...
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38 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 ...
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1answer
44 views

Parametric Bootstrap Capture Recapture

I am using the (one sample) capture recapture for estimating hidden human population. One sample method uses purely frequencies of capture to estimate population. One of my colleague suggested ...
1
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1answer
84 views

How to statistically test the predictability of evolution? [closed]

Can anyone recommend me an experimental study which tries to test the predictability of evolution? The closest works I found are the studies of fluctuation tests (f.e. classical study of Luria & ...
14
votes
1answer
381 views

How statistically significant was the “sweaty T-shirt” experiment?

An Overview of the Experiment. In 1995 there was an experiment that involves young people smelling T-shirts worn by another gender and rating their preference. The researchers found that people ...
3
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21 views

What techniques can be used to link environmental conditions to crop yield?

Im interested in how we can determine what are the optimal conditions for crops and how deviations from these optimal conditions affect yield. In the literature I have found two main approaches and I ...
3
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1answer
99 views

Why perform imputation?

Genetics datasets contain measurements for millions of single nucleotide polymorphisms (SNPs). Some (usually small) percentage of these values are of low confidence, and are labeled as missing values. ...
9
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3answers
405 views

Do biological phenomena follow Gaussian statistics?

I have recently entered the life sciences (from physics). I am concerned about the use of p values in the life sciences literature. For example, in this article, they test 9 - 12 rats in a control ...
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0answers
15 views

What is the best aCGH normalization procedure for hyper-ploid tumor samples?

I'm currently working on aCGH data of Triple Negative Breast Cancer patients xenografts and primary tumor samples. A substantial amount of my samples is highly aberrated which leads to offsets of the ...
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0answers
25 views

Does anyone use bootstrapping to report mass gain during experiment?

When performing an experiment to report gain of body mass in an experiment, do any of you know of a paper whose authors have used a bootstrap to improve their confidence intervals? I have a n = 10 ...
5
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0answers
77 views

Understanding F-statistics in population genetics

I am reading a classical Weir and Cockerham 1984 paper about Fst estimation. At the beginning (first page, right column), they define 3 statistics. $F$ is the correlation of genes within individuals ...
2
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0answers
79 views

Efficient algorithm to calculate various population divergence statistics

Intro and description of the data I am simulating the evolution of very long DNA sequences. The model works well, is performant and will output data in the following kind of fasta format ...
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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 ...
4
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1answer
643 views

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

There have been papers discussing this, and whether the abstinence period should be 1 week, 2 weeks or other [1, 2]. Some think the time to maximum ejaculation volume is even longer than this. doi: ...
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1answer
3k views

How should species density be calculated for a clumped distribution?

Lets imagine 5 plots of different size are sampled for a target species: ...
6
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1answer
53 views

Independent contrasts with non-homologous traits

I have morphometric measurements for a trait across various animal taxa, and would like to study the relationship between the size of this trait, and the animals' body size. In theory, I can account ...
2
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1answer
85 views

How to calculate the Jaccard index [closed]

I want to calculate the Jaccard index between two compounds. What is the algorithm? I have searched for it, it just gives the formula but how to apply it on compounds is not known to me. Can you help? ...
9
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1answer
1k views

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

The simplest description of the difference between these two approaches that I have found are on this site who summarise the difference as: Mechanistic model: a hypothesized relationship between the ...
6
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1answer
98 views

What are the units of Phylogenetic Independent Contrasts (PICs)

PICs are a popular phylogenetic comparative method and I was wondering what units the actual contrasts are in. I want to say they are unitless but I am not entirely sure.
4
votes
1answer
104 views

Bayes theorem for mutations

MEN 2A is a dominant inherited disease caused by a mutation in the RET proto-oncogene. The probability of being sick when you have the mutation of the RET proto-oncogene varies with age and is assumed ...
11
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1answer
140 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 ...
2
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1answer
102 views

Correct/complete representation of RTPCR statistics

In papers reporting a relative quantification of gene expression by RTPCR, I often see a bar chart with mean ± standard error or deviation, with the deviation belonging to biological replicates. This ...
2
votes
1answer
69 views

Comparing gene expression levels between control and disease at different time points

I have a data set with expression levels of a list of genes, measured in replicate at two different time points between two groups; a control group and a disease group. I want to identify the changes ...
0
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1answer
245 views

How to select genes before log2 ratio on a RNASeq gene expression matrix, based on signal median

I want to transform a TCGA mRNA expression matrix (in linear data format) to log2-ratios and then run a feature (gene) selection, selecting the 1000 most variant genes (genes with higher standard ...
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0answers
19 views

How to study the number of herbivores per type of tree and time of day?

Suppose I want to find out the number of herbivores in different kinds of trees, and also compare the numbers between day and night. How would this kind of study be run in practice? It easy to think ...
3
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2answers
158 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 ...
9
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1answer
105 views

Statistical method for characterizing the relationship between body mass and metabolic rate

There is a dataset that contains body mass ($x$) and metabolic rate ($y$) from many different organisms. It is common to fit the data to the model of the form $y=ax^b$ and estimate the parameters $a$ ...
1
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0answers
52 views

Cigarette consumption dose-response function WRT health outcomes

I'm curious how health risks (mortality, lifetime probability of cancer, etc) change with cigarette consumption. Specifically, treatring cigarette consumption like a continuous variable, rather than ...
4
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1answer
133 views

Why estimate linear and full (linear, quadratic, and correlational) selection coefficients separately?

"We then fitted a linear regression including all three life-history traits to estimate the vector of linear selection gradients, β, for each sex (Lande and Arnold 1983). A quadratic regression ...
2
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1answer
349 views

(Updated question) Problem with Fold-change mean compared to absolute data (in qPCR)

For the problem below I am aware of the statistics involved but just can't get my finger around the following: In biology we use qPCR to measure gene expression or basically number of mRNA copies. It ...
3
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1answer
47 views

Using Canonical Correspondence Analysis on matrices with missing data

I have a matrix of sites where not all the environmental variables I want to assess were sampled. In other words, there are sites with the whole set of variables sampled, and there are other sites ...
4
votes
1answer
189 views

What equation to compare protein isoforms in a Western Blot?

The protein isoforms I am interested in comparing appear as distinct bands on the gel I have already run. I have an Excel sheet with optical density measurements I obtained using ImageJ; it looks ...
2
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1answer
53 views

Data Bias in protein-protein interactions data

Databases like STRING have so many predicted as well as experimental interactions data for many organisms.However there is a bias in the data which they have?. a)The first is gene co-occurrence ...
3
votes
1answer
58 views

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

Recently the UK government suggested that all adults over the age of 50, without exception, would benefit from taking statins. I have an elderly female relative who may, or may not have had a minor ...
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2answers
90 views

Cancer cure statistics questions

I have a question about cancer cure statistics. Many of the cancer literature or databases I have come across speak about 5 year or 10 year survival rates. In this case survival means that the patient ...
2
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2answers
82 views

Valid comparison of gene expression between several genes in several cell lines

We have gene expression data (Affimetrix mRNA gene expression results) for several cell lines, over a set of genes. Our goal would be to be able to compare relative gene expression for genes over the ...
10
votes
3answers
1k views

How best to count bees entering and leaving a hive to measure hive activity?

This is my first question here, so I apologize for all mistakes I could have possibly made. I'm a high school student in East-Central Europe and I need to complete some research for a biology contest ...
2
votes
3answers
688 views

Why cancer mutations do accumulate sequentially?

According to Knudson hypothesis, cancer mutations accumulate in order. Statistics says, that cancer probability increases as sixth order of age, which may mean six consequential steps to cancer. But, ...
2
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1answer
72 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 ...