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31. A lumber company is interested in seeing if the number of board feet per tree has decreased since moving to a new location of timber. In the past, the company has had an average of 93 board feet per tree. It believes that the mean production has decreased since changing locations. A random sample of 35 trees yields v = 89. Assume the population standard deviation is o = 20. You are testing Ho: H = 93 vs Hail