Can pleasant smells improve leaming? Researchers timed 21 subjects as they tried to complete paper-and-pencil mazes. Each subject attempted a maze both with and without the presence of a
floral aroma. Subjects were randomized with respect to whether they did the scented trial first or second. Suppose a paired t-test is to be performed to determine whether there is evidence to indicate
that the time to complete the maze is faster in scented trials compared to unscented trials, on average. The summary statistics for the difference in time to complete the maze (in seconds) between
the unscented and scented trials (unscented-scented) are x-3.85 and s 13.01. How many degrees of freedom does the 1-statistic have?
Choose the correct answer below.
OA. 41
OB. 40
OC. 21
OD. 20
OE 19