Neverslip, Inc., produces belts for industrial use. As part of its continuous process improvement program, Neverslip has decided to monitor on-time shipments of its products. Suppose a random sample of 140 shipments was taken from shipping records for the last quarter and the shipment was recorded as being either

“on-time” or “late.” The results of the sample are contained in the file Neverslip.

a. Using the randomly sampled data, calculate a 90%

confidence interval estimate for the true population proportion, p, for on-time shipments for Neverslip.

b. What is the margin of error for the confidence interval calculated in part a?

c. One of Neverslip’s commitments to its customers is that 95% of all shipments will arrive on time. Based on the confidence interval calculated in part

a, is Neverslip meeting its on-time commitment?