An economist found that a random sample of 45 high school teachers had an average annual salary of $58,230.  A previous study showed that the population standard deviation is $4450. Find the 90% confidence interval for µ, the average annual salary of all high school teachers. A.  (54607.2 , 58372.8)  B. (56929.8 , 59530.2)  C. (54837.9 , 58142.1)  D. (57138.3 ,  59321.2)

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