A manufacturer of detergent claims that the contents of boxes sold weigh on average at least 20 ounces. The distribution of weight is known to be normal, with a standard deviation of 0.5 ounces. A random sample of 25 boxes yielded a sample mean weight of 19.92 ounces. Test at the 5% significance level the null hypothesis that the population mean weight is at least 20 ounces. What are the null and alternative hypotheses for this test? A. Ho: =20 H = 19.92 c. Ho: 20 H: 20 D. Ho: =20 H: 20 For this test at the significance level & with sample mean x, hypothesized mean , population standard deviation , sample size n, and Z or Z/2, what is the form of the decision rule? x-Ho A. Reject Ho if Z Determine the appropriate value(s) of -Za, Za or Za/2. (Round to three decimal places as needed. Use a comma to separate answers as needed.)