Sora-Tobu-Jutan Technologies wants to estimate the aver-age time it takes to complete the assembly of its new robot vacuum cleaner. After allowing enough time for the workers to learn the new assembly procedures, supervisors choose 15 assemblies to observe. For these 15 assemblies, average assembly time is 38.4 minutes; the standard deviation of the sample assembly times is 5.6 minutes.
a. What is the population represented by the sample?
b. Construct and interpret a 95% confidence interval estimate of average assembly time required for the population of these units now being assembled at your company. Assume that the population distribution of assembly times is normal.
c. For your answer in part b, identify the margin of error and the standard error term.