Question: A manufacturing company produces steel housing for electrical equipment. The main

component part of the housing is steel trough that is made out of a 14-gauge steel coil. It is produced

using a 250-ton progressive punch press with a wipe down operation that puts two 90 degree forms in

the flat steel to make the trough. The distance from one side of the form to the other is critical because

of weatherproofing in outdoor applications. The company requires that the width of the trough be

between 8.31 inches and 8.61 inches. The file "Trough" contains the widths of the troughs, in inches, for

a sample of n=49.

a) Compute the mean, Median, first quartile, and third quartile.

b) Compute the range, interquartile range, variance, standard deviation and coefficient of

variation.

c) Interpret the measure of central tendency and variation within the context of this problem. Why

should the company be concerned about the central tendency and variation?

d) At the 0.10, 0.05 and 0.01 level of significance, is there evidence that the mean width of the

troughs is different from 8.46 inches?

e) What assumption about the population distribution is needed in order to conduct the

hypothesis test in (a)