The manager of a grocery store wants to determine whether the amount of water contained in 1 gallon bottle purchased from a nationally known manufacturer actually average 1 gallon. It is known from the manufacturer's specifications that the standard deviation of the amount of water is equal to 0.02 gallon. A random sample of 32 bottles is selected, and the mean amount of water per 1 gallon can is found to be 0.995 gallon. Calculate the test statistic.