Researchers at the Mayo Clinic have studied the effect of sound levels on patient healing and have found a significant association (louder hospital ambient sound level is associated with slower postsurgical healing). Based on the Mayo Clinic's experience, Ardmore Hospital installed a new vinyl flooring that is supposed to reduce the mean sound level (decibels) in the hospital corridors. The sound level is measured at five randomly selected times in the main corridor. Does the evidence convince you that the mean sound level has been reduced? Select the appropriate hypotheses. (a-3) Calculate the test statistic. (Round your answer to 4 decimal places. Input the answer as a positive value.) At = .05, has the variance changed? Choose the correct hypothesis. a h (b-3) What is the test statistic? (Round the test statistic value to 4 decimal places.)