In: Statistics and Probability
Comparing two groups. Identify a situation in your field of work (which is education) that might call for the use of a t test for two samples. Which test will be used (independent or dependent)? Justify your choice, and of course clearly identify the variables (independent and dependent).
Comparing two groups
Suppose we want to compare two groups of students if one group is provided advanced teaching method and other group is provided traditional teaching method. Students in the each group are selected randomly by using simple random sampling. After end of the semester, same exam is held for both groups and marks for the students in both groups are compared. We want to find out if there is any significant increase in the average marks of the students in the group who provided an advanced teaching.
For the above scenario, both groups of the students are independent from each other. These groups are not related. So, we need to use two sample t-test for independent samples (independent samples t-test). For this test, dependent variable is marks of the student and independent variable is method of teaching.
Let us see one more scenario. Suppose we want to check the effect of advance teaching method. A random sample of 30 students is selected. For the first semester students were provided a traditional teaching method and marks were recorded at the end of first semester. For the next semester, an advanced teaching method is used for the same sample of 30 students and marks were recorded. We want to check the effect on marks of the student before and after using an advanced teaching method.
For this scenario, both samples (before and after) are dependent or related to each other. Marks of same students are used for before and after using advance teaching method. So, in this case we will use the dependent t test or paired t test.