A bolt manufacturer is very concerned about the consistency with which his machines produce bolts. The bolts should be 0.18 centimeters in diameter. The variance of the bolts should be 0.015. A random sample of 18 bolts has an average diameter of 0.19cm with a standard deviation of 0.0607. Can the manufacturer conclude that the bolts vary from the required variance at α=0.1 level?
Step 1: State the null and alternative hypothesis
Step 2: Determine the critical value(s) of the test statistic. If the test is two-tailed, separate the values with a comma. Round your answer to three decimal places.
Step 3: Determine the value of the test statistic
Step 4: Reject or fail to reject
The sample variance is
Conclusion : The manufacturer can conclude that the bolts vary from the required variance at α=0.1 level.
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