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Questions tagged [t-test]

Related to statistical hypothesis testing. Most software packages used for statistical analysis (including R) provide functions for performing the t-test. Use this tag for questions related to the t-test.

The t-test is also known as the "Student's t-test" after the pseudonym of its inventor. It is used for comparing the means of two samples, or the mean of one sample (or even parameter estimates) with a specified value. See the Wikipedia article for more details. Refer to the R documentation for details on the t.test function arguments and return values.

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T-Test to every possible combination of samples

I'm new at R language, so I'm sorry if my question is too basic, but here we go... I'm working with microarray analysis , utilizing the R software and right now I have to do a t-test to every possible combination of samples of my two analyzed…
Marcelo Falchetti
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barplot, t-test from different categories in r

I have data of the following format from several org (showing a to d here, some have 3 and some have 4 samples): org unfiltered filtered org_a 50.82 67.82 org_a 57.72 58.31 org_a 67.82 55.72 org_a 58.31 52.72 org_b 55.72 …
bio8
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AB Testing Analysis in R. prop.test() OR t.test()

AB Testing Scenario: Testing a new design of REGISTRATION PAGE ENTRY BUTTON on web - the user clicking on the BUTTON will be taken to a new page where in which the user can supply the email and create a registered account. The Sample is chosen…
Jo Geo
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1 sample t-test from summarized data in R

I can perform a 1 sample t-test in R with the t.test command. This requires actual sets of data. I can't use summary statistics (sample size, sample mean, standard deviation). I can work around this utilizing the BSDA package. But are there any…
Display name
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Conducting multiple t-tests without using limma

I am trying to conduct a paired t-test and generate a resulting p-value for some methylation data that I have. The data is in 6 columns: 3 for each patient before treatment and 3 for each patient after treatment. There is one row for each gene…
M Dybala
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Unpaired but not paired ttest loop in R working

I have a loop that goes through a dataframe, runs ttests and stores the resulting p-value of each ttest in another dataframe. Here is the loop where 'mydata' is the dataframe that the ttests are being run on. 'mydata' is a dataframe with 4…
user8271479
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Histogram to decide whether two distributions have the same shape in R

I would like to create a diagram in R as shown below (right) where i can show the distribution of my dummy variable, reservation (1) or walk-in (0), as separate. This in order to do a correct analysis of the Mann-Whitney U test. I want to make the…
Emily
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Python: Statistics T-test

I am using python 3.6 to run some statistics test on a data-set. What I am trying to accomplish is to run a t-test between the data-set and the trend line to determine the statistical significance. I and using scipy to do this however I am not sure…
CPG
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Python - Performing t-test of estimate with standard error

I'm wondering if there is a way to perform a two-tailed t-test for an estimate, given its standard error and the number of degrees of freedom? The estimate is read from another software. I have been using the t.dist.2t(abs(estimate/SE), df) in…
branwen85
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I want to run a t-test, how should I organise my data to do so?

In R, I want to run a statistical test to compare the averages between two categories, but I do not know how to organise my data to do so. Mock example My data is organised like: structure(list(age = c(39, 45, 83, 68, 48, 52, 66, 50, 61, 67), gender…
francoiskroll
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How to construct a table from a t-test in R

I was provided with three t-tests: Two Sample t-test data: cammol by gender t = -3.8406, df = 175, p-value = 0.0001714 alternative hypothesis: true difference in means is not equal to 0 95 percent confidence interval: -0.11460843…
jhlee
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Sample t-test by row in R

My data has repeats in columns for two variables BFP and DAP. There are 10 rows of these - with each row named after a gene. I am trying to compare the means of AFP and APP for each gene via a two-sample t-test with unequal variances, and assign the…
Helpful_Triazole
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T-Test and PValue- Math.Net Numerics class

Is there a method to get the ttest-value and P-Value from the StudentT class. I am trying to calculate those values from this library : https://numerics.mathdotnet.com/api/MathNet.Numerics.Distributions/StudentT.htm The excel equivalent function is…
Skanda
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One sided t-test for linear regression?

I have problems with this. I am trying to do a linear regression and test the slope. The t-test checks if the slope is far away from 0. The slope can be negative or positive. I am only interested in negative slopes. In this example, the slope is…
Orvar Korvar
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Need to loop through columns to perform t tests?

So I have a customer survey, and I need to determine if there are significant differences between the four areas. I obviously want to do a t-test on these, and here is my current R solution. `for (i in colnames(c_survey)) assign(i,…
CapnShanty
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