A random sample of 80 eighth grade students' scores on a national mathematics assessment test has a mean score of 286. This test result prompts a state school administrator to declare that the mean score for the state's eighth graders on this exam is more than 280. Assume that the population standard deviation is 30. At a=0.11, is there enough evidence to support the administrator's claim? Complete parts (a) through (e). CIT z (a) Write the claim mathematically and identify Ho and H. Choose the correct answer below. OA. Ho: 280 OB. Ho: 280 (claim) H₂H>280 OC. Ho: H5280 (claim) H>280 Ha H>280 (claim) OD. Ho: 2280 (claim) VE. Ho: $280 QF. Ho<280 H₂H 280 H>280 (claim) H:2280 (claim) 21 (b) Find the standardized test statistic z, and its corresponding area. NS Z= (Round to two decimal places as needed.) MI (b) Find the standardized test statistic z, and its corresponding area. The standardized test statistic is

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