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You work for a company that produces electronics with integrated circuits. One of your products is called a "shift register." This product is designed to automatically shut down if its operating temperature exceeds 175 degrees Celsius. The manufacturing process has been designed to have a standard deviation of o = 0.4 degrees Celsius. You test a random sample 18 shift registers, and you record the following shut- down temperatures. Construct a 90% confidence interval for the overall mean shutdown-temperature. 175.68 174.54 174.5 175.1 175.11 175.43 175.3 174.93 173.97 175.21 175.22 174.99 175.07 174.77 174.91 174.81 175.47 174.86 (Checksum: 3149.87) es a) Find the critical value and or . Critical Value: b) Find the confidence interval