The average diameter of a bolt produced by a machine is 16

Last updated: 7/10/2022

The average diameter of a bolt produced by a machine is 16 mm. To determine if the sample mean differs from the population mean, a sample of 9 bolts is inspected. The diameters (in mm) of 9 bolts are: 16.020, 16.031, 16.017, 16.024, 16.028, 16.023, 16.025, 16.019, and 16.024. Is there a significant difference between the sample mean and the population mean? (Use: the tabulated t-value for 8 degrees of freedom at a 95% level of significance is 2.31.) Yes, because 16.02 > 2.31. No, because 16.02 > 2.31. Yes, because 1.06 < 2.31. No, because 1.06 < 2.31.