24.1 Means of two independent samples
In one study, two different groups of students were used: one group used a mobile phone, and a different group did not use a mobile phone. The reaction time for each student was measured in a driving simulator.
The study uses two groups with different treatments: one group using a mobile phone while driving, and a different group not using a mobile phone while driving.
The data are not paired; instead, the means of two separate (or independent) samples are being compared. (The data would be paired if each student was measured twice: once using a phone, and once without using a phone.)
Consider the RQ:
For students, what is the difference between the mean reaction time while driving when using a mobile phone and the mean reaction time while driving when not using a mobile phone?
The data are shown below.