# Biostatistics in Medicine : The "t" test

**This article describes about the "t" test in Biostatistics. Read to know where does the t test come into use and also the significance of t test in sampling.**

Sampling and Sampling test are needed to obtain statistical data and the "t" test is used when the sample size is small, usually the data given is less than 30.

The "t" test was first derived by W.S. Gosset in 1908 who had published the same under the name "student" from which it is known as the student's "t" test.

The pre-requisites to use the **t** test are :

1. The observations or data are independent of each other.

2. The population standard deviation is not known.

3. The distribution of population is of a normal type.

Uses of **t** test are are follows:

The **t** test is used for testing the significance or importance of :

1. The mean of sample

2. To compare two samples and their mean values

3. Correlation coefficient.**t** test regarding single mean :

This is used to test the significance of difference between sample mean and population mean or whether the sample has been drawn from the population with mean in case of small sample (sample size "n" < 30).

Reference: http://en.wikipedia.org/wiki/Student%27s_t-test