If you were conducting the study above, would you perform a one- or a two-tailed test? Why?

Billie wishes to test the hypothesis that overweight individuals tend tot eat faster than normal weight individuals. To test this hypothesis, she has two assistants sit at a McDonald's restaurant and identify individuals who order Big Mac special meals (Big Mac, large fries and large soda) for lunch. The "Big Mackers" as they are affectionately called by the assistants, are classified as overweight, normal-weight and neither overweight nor normal weight. The assistants identify 10 overweight and 30 normal-weight Big-Mackers. The assistants record the amount of time it takes for the individuals to complete their meals. The SPSS data file contains two variables, a grouping variable with two levels, overweight (=1) and normal weight (=2), and time in seconds to eat the meal.