Problem: A researcher is interested in whether people's stress levels vary depending on the time of year. The researcher recruits five participants for their study. They ask the participants in mid-July on a scale from 1 to 20. How stressed they felt on average (where a higher score means greater stress) Then, in mid-January, they asked the same five participants again to report how stressed they felt on average. Their average stress levels in July were 1 and in January they were 15.
A) t = -0.25
B) t = -2.00
C) t = -4.49
D) t = -4.00