The mean voltage and standard deviation of 9 batteries from each manufacturer were [fl measured. The results are summarized in the following table) U 3 What type of hypothesis test should be performed? What is the test statistic? Ex: 0.123 What is the number of degrees of freedom? Does sufficient evidence exist to support the claim that the voltage of the batteries made by the two manufacturers is different at the a = 0.05 signicance level