What test will be be using to test the difference in means? code example

Example 1: what is testng

TESTNG: TestNextGeneration
    -> What is TestNG?
        - TestNG is a UNIT TESTING TOOL.
        - It was inspired by JUNIT, but a little bit more advanced than JUNIT.
        - TESTNG helps us create certain testing flow/structure using 
        its ANNOTATIONS.
-->  some of the annotation from TestNG are
    @Test
    @BeforeSuite
    @AfterSuite
    @BeforeTest
    @AfterTest
    @BeforeGroups
    @AfterGroups
    @BeforeClass
    @AfterClass
    @BeforeMethod
    @AfterMethod

Example 2: what does a test have

It is documentation which describes step by step how to perform testing. 

It includes: 
	- test case ID (TC ID)
	- test case name (TC Name)
	- pre-condition
	- step definitions
	- test data
	- expected/actual result
	- pass/fail

Tester creates test cases.