Final answer:
In a threshold detection experiment, an absolute threshold of 7 units indicates the minimum stimulus intensity required to be detected 50% of the time, which reflects the sensitivity level of a person's sensory system for that particular stimulus.
Step-by-step explanation:
In a threshold detection experiment, obtaining an absolute threshold of 7 units means that this is the minimum amount of stimulus energy that needs to be present for the stimulus to be detected 50% of the time. It marks the point at which a person starts to detect a stimulus and represents the sensitivity of the sensory system to the relevant stimuli.
For example, if the absolute threshold for hearing a certain tone is 7 units, then any sound below 7 units would not be detected half of the time by the average person, and sounds at or above 7 units would be detected by them half of the time. Conversely, stimuli that are below this threshold level could be considered subliminal, as we might receive them but not be consciously aware of them. In comparison, a difference threshold or just noticeable difference (jnd) involves the minimum difference in the intensity of the stimulus required to perceive a difference between two stimuli.