The manufacturer of a particular brand of crackers claims that the mean weight for the boxes of crackers is 388 grams.To test this claim, a group of students carefully weighed the contents of 100 boxes, and found a mean weight of 380 grams with standard deviation 30 grams.We want to use this information to decide if the mean weight is less than 388 grams.

Calculate the test statistic.

(Please round to 2 decimals.)