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Hypothesis Testing: z test

1. Suppose you are working with a data set that is normally distributed with a mean of 400 and a standard deviation of 20. Determine the value of x such that only 1% of the values are greater than x.

2. When the rod shearing process at Stockton Steel is "in control" it produces rods with a mean length of 120 inches. Periodically, quality control inspectors select a random sample of 36 rods. If the mean length of sampled rods is too long or too short, the shearing process is shut down. The null hypothesis is _________.
n = 36
μ = 120
μ ≠120
n ≠36

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