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A battery company manufactures batteries that the CEO claims will last an average of 300 hours under normal use. A researcher randomly selected 22 batteries from the production line and tested these batteries. The tested batteries had a mean life span of 288 hours with a standard deviation of 53.4 hours. Do we have enough evidence to conclude that the mean lifetime is less than the 300 hours? Assume the population is normally distributed. Use a 5% level of signicance for each test. What is the test statistic for this hypothesis test? Round the value to 2 decimal places