Stack Overflow
Stack Overflow

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.

494 questions
-1
votes
2 answers

Creating a t-test loop over a dataframe using an index

So, let's say I have a 1000-row, 6-column dataframe, the columns are a1, a2, b1, b2, c1, c2. I want to run some t-tests using a's, b's, and c's and get an output df with 3 columns for the t-values of a-b-c and another three for the significance…
arthur_fleck
  • 3
  • 3
-1
votes
1 answer

Doubts about t.test results

I have a vector with 385 numbers ranging from 2000 to 5200 and I am asked to test whether the mean is greater than 5500. I tried this: t.test(tabla2$`Precio max`, y = NULL, alternative="g", mu=5500,paired = FALSE, conf.level=0.95) and the result…
David Contreras
  • 13
  • 4
-1
votes
1 answer

Performing T-Test on Time Series

My boss asked me to perform a T-Test to test the significance for a certain metric we use called conversion rate. I have collected 18 months worth of data for this metric dating April 1, 2017 - September 30th, 2018. He initially told me to collect…
Keith
  • 103
  • 1
  • 9
-1
votes
1 answer

How do I compute point-by-point t tests between two 50 data point vectors?

I have a data frame with 3 variables and 50 instances (ID,pre and post).somewhat like this ID<- c("1","2","3","4","5","6","7","8","9","10") pre<-…
shanky
  • 11
-1
votes
1 answer

Statistic analysis of two groups

i need to analyze this data. Tried with anova and independent t-test but i have no results. i appreciate your comments Group Biomass 1 3876 3876 3875 2 4016 4016 4016 Values represent area as growth
Biologist24
  • 1
-1
votes
2 answers

Multiple ttests

I want to perform multiple ttests on data in the following format first column is "id" with values (for example) 1,1,1,2,2,2 second column is "ratios" with values 0.2, 0.18, 0.3, 1.5, 1.4, 1.6 for each instance of "id" I want to test all ratio…
brtw
  • 1
-1
votes
2 answers

How to run a t-test on a subset of data

First, is this dataset in a tidy form for a t-test? https://i.stack.imgur.com/tMK6R.png Second, I'm trying to do a two sample t-test to compare the means at time 3 of treatment a and b for 'outcome 1'. How would I go about doing this? Sample…
DiscoR
  • 247
  • 2
  • 11
-2
votes
1 answer

Paired t-test for multiple variables in several time points

My previous post was deleted addressing me to other post which actually it is not useful for my purpose, because this post only has 2 columns to compare My code data_samp <- structure(list(paciente = structure(c(6036, 6299, 6324, 6457, 6201, 6092,…
Javier Hernando
  • 181
  • 7
-2
votes
1 answer

T.test for each row in R

I am working with two data frames both with 20502 rows, and I want to preform a t.test with the 1st row of one data frame and the 1st of the other data frame and so one until the 20502 row of the two data frames. ps: I have missing values (NA) in my…
André Conceição
  • 13
  • 1
  • 2
-3
votes
1 answer

How to perform a two sample t test in python using any statistics library similar to R?

I can do this in R for 2 sample T-test: t.test(x, y = NULL, alternative = c("two.sided", "less", "greater"), mu = 0, paired = FALSE, var.equal = FALSE, conf.level = 0.95) I want some function where I can pass this mu(difference in mean)…
Ankit Agrawal
  • 11
  • 1
  • 4
-4
votes
1 answer

Optimize data for t.test to avoid "data are essentially constant" error

There are several StackOverflow posts about situation where t.test() in R produce an error saying "data are essentially constant", this is due to that there is not enough difference between the groups (there is no variation) to run the t.test().…
Thend
  • 95
  • 7
-4
votes
1 answer

one way anova for multiple classes either matlab or python

i have 4 classes of size (72,22,22) and i want to do anova1 for each pair of the (22,22) in those classes . for example; i wanna grab, let's say, pair (2,3) in each class and do the anova for each pair in the 4 arrays, so the output would be an…
Abdul
  • 1
  • 3
1 2 3
…
32
33