An engineer is comparing voltages for two types of batteries (K and Q) using a sample of 39 type K batteries and a sample of 57 type Q batteries. The type K batteries have a mean voltage of 8.55, and the population standard deviation is known to be 0.683. The type Q batteries have a mean voltage of 8.82, and the population standard deviation is known to be 0.791. Conduct a hypothesis test for the conjecture that the mean voltage for these two types of batteries is different. Let μ1 be the true mean voltage for type K batteries and μ2 be the true mean voltage for type Q batteries. Use a 0.02 level of significance. Step 1 of 5 : State the null and alternative hypotheses for the test.