SOLUTION: Perform a Hypothesis test for the population mean. Assume that preliminary data analyses indicate that it is reasonable to apply the z-test. Use the critical value approach.
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Question 862643: Perform a Hypothesis test for the population mean. Assume that preliminary data analyses indicate that it is reasonable to apply the z-test. Use the critical value approach.
A manufacturer makes steel bars that are supposed to have a mean length of 50cm. A retailer suspects that the bars are running too long. A sample of 55 bars are taken and their mean length is determined to be 51cm. Using a 1% level of significance, perform a hypothesis test to determine whether the population mean is greater then 50 cm. Assume that the population standard deviation is 3.6cm. Answer by ewatrrr(24785) (Show Source):
Hi
z = (51-50)/(3.6/sqrt(55)) = 2.06
CI z -value
90% z =1.645
92% z = 1.751
95% z = 1.96
98% z = 2.326
99% z = 2.576
2.06 < 2.576 Do not reject Ho at the 1% level of significance
