A matched-pairs study evaluated a typing tutor's effect on speed. For $6$ participants, the differences (post-tutor minus pre-tutor) in typing speeds are:
Mean difference: $(\bar{d}=1.8)$ words per minute
Standard deviation of differences: $(s_d=1.5)$ words per minute
Sample size: $(n=6)$
Calculate the test statistic for a right-tailed hypothesis test of the claim that the typing tutor increases typing speed.