What is T- Test | Meaning | Types | Example

Welcome to Research Hub.

A t-test is the final statistical measure

for determining differences between two means

that may or may not be related.

The testing uses randomly selected samples

from the two categories or groups.

It is a statistical method in which samples are chosen randomly.

There is no perfect normal distribution.

A t-test is a statistical test

that is used to compare the means of two groups.

It is often used in hypothesis testing

to determine whether a process or treatment

actually has an effect on the population of interest,

or whether two groups are different from one another.

Okay, when to use a t-test.

A t-test can only be used

when comparing the means of two groups,

a.k.a. pairwise comparison.

If you want to compare more than two groups

or if you want to do multiple pairwise comparisons,

use an ANOVA test or a post-hoc test.

The t-test is a parametric test of difference,

meaning that it makes the same assumptions about your data

as other parametric tests.

The t-test assumes your data

1, are independent,

2, are approximately normally distributed

3, have a similar amount of variance

within each group being compared,

a.k.a. homogeneity of variance.

Types of t-test.

1, one-sample t-test.

The one-sample t-test is a statistical method that helps determine

if the mean of a single sample is significantly different

from a known or supposed population mean.

It is valuable for working with small sample sizes

and normally distributed data.

The test allows researchers and analysts

to draw meaningful conclusions from limited data.

The one-sample t-test involves calculating the t-statistic

by taking the mean of the sample,

subtracting the assumed population mean,

and then dividing by the standard error of the mean.

It is widely used in research across several domains

to examine if a sample is representative

of a larger population.

2, independent two-sample t-test.

This is the test conducted when samples

from two different groups, species, or populations

are studied and compared.

It is also known as an independent t-test.

The two-sample t-test,

also known as the independent samples t-test,

is a method used to test

whether the unknown population means of two groups

are equal or not.

For example, if a teacher wants to compare

the height of male students and female students,

she would use the independent two-sample test.

The t-test formula used to calculate this is...

The need to compare the means of height

between two independent group, male and female,

independent samples t-test could be performed.

This hypothesis testing is conducted when two groups

belong to the same population or group.

The groups are studied either at two different times

or under two varied conditions.

The paired-samples t-test is a statistical test

used to determine if two paired groups

are significantly different from each other

on your variable of interest.

Your variable of interest should be continuous,

be normally distributed.

The formula used to obtain the t-value is...

For equal-variance t-test,

this test is conducted

when the sample size in each group or population

is the same, or the variance of the two data sets

is similar.

It is also referred to as pooled t-test.

The formula applied:

mean 1 and mean 2 equal average value

of each set of samples.

Variable 1 and variable 2 equal variants

of each set of samples.

n1 and n2 equal number of records in each set.

5, unequal-variance t-test.

The unequal-variance testing is used

when the variance and the number of samples in each group

are different.

It is often referred to as Welch's test,

and the formula is...

mean 1 and mean 2 equals average value

of each set of samples.

Var 1 and var 2 equals variance of each set of samples.

n1 and n2 equals number of records in each set.

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