Question

A supplier states that the average diameter of optical glass plates is 37.50 mm. The specifications are 37.50 mm ± .40 mm. A shipment of 500 plates is received and a sample of 10 plates is selected and the diameters of each are measured. The following data are obtained:
37.42 mm 37.84 ,37.50 , 37.48 , 37.75 , 37.63 , 37.82, 37.78, 37.79, 37.51
Does the entire population have an average diameter of 37.5 mm? Test at a level of significance of .05.

Answer 1