SAHILA MAHAJAN

GROUP-6

ROLL NO-37

T-test for Comparing Group Means

 The t-test is used to determine whether two groups are significantly different in their means. There are 3 types of t-tests: 

1) One sample t-test                                                                                                  
2) Independent sample t-test                                                                                     
3) Paired samples t-test

1.     One Sample t-test:
A one sample t-test means  ONE GROUP (e.g., class of 8th grade students) who you are comparing to A KNOWN MEAN SCORE (say the national mean on a normed test).

2.     Independent Sample t-test:
A two sample t-test means that you have TWO GROUPS (e.g.,class of 8th grade students compared to LAST YEAR'S group of students).

3.     Paired Sample t-test:
A two sample t-test means that TWO GROUPS that you are comparing against one another, but the members of each group are related in some way to a specific member of the other group (e.g., study partners, siblings, married couples, etc.)

Unrelated groups

Unrelated groups, also called unpaired groups or independent groups, are groups in which the cases in each group are different. Often we are investigating differences in individuals, which means that when comparing two groups, an individual in one group cannot also be a member of the other group and vice versa. An example would be gender - an individual would have to be classified as either male or female - not both.  

Source:http://bold-ed.com/ttest.htm