A chemical company is interested in determining if the population mean chemical yield of a new catalyst is greater than an older catalyst. The old catalyst has a population mean chemical yield of 96.7 kg/h. The company collects a sample of 49 runs using the new catalyst and observes a mean of 157.63 kg/h. They know the population standard deviation is 11 kg/h. Calculate the test statistic associated with this hypothesis test. NOTE: you must first decide whether to calculate z or t. If you calculate z, round to 2 decimal places. If you calculate t, round to 3 decimal places.