You are interested to know if eating spicy food has an effect on a person's mood. You run a study that rates each of six subject's mood prior to eating a habanero pepper and immediately following finishing the pepper. Printed below is a set of difference scores for each of the six subject's mood from pre-pepper to post-pepper. Calculate the t-statistic for this comparison. Round your answer to two decimal places.

9, 9, 10, 3, 3, -3