Arsenic is an element that occurs naturally in groundwater, but a mean greater than 8.0 parts per billion indicates that the groundwater has been contaminated. Local officials are concerned about a well in an area of the city near a factory. On 50 consecutive days, water was randomly sampled from the well. The mean arsenic levels of these 50 measurements was 8.34 ppb with sample standard deviation 0.823 ppb. Is this enough evidence that the groundwater has been contaminated? Calculate the value of the t-test statistic. Round your final answer to 2 decimal places