A manufacturer claims that the thickness of the steel plates it produces is 61 mils (thousandth of an inch). Car manufacturer's quality control officer regularly checks the claim. From a recent shipment he took a random sample of 50 plates: the sample mean and variance are 61.3 and 1.22, respectively. In order to verify that the manufacturer's claim is accurate, what should his null hypothesis be and should it be accepted at 10% significance level?

Which test is used: Two-Tail, Upper-Tail, Lower-Tail?

Hypotheses: Ho: Ha:

Conclusion:Reject or fail to reject null hypothesis?