[EX02-204] Delco Products, a division of General Motors, produces a bracket that is used as part of a power doorlock assembly. The length of this bracket is constantly being monitored. A sample of 30 power door brackets had the following lengths (in millimeters):

a. Without doing any calculations, what would you estimate for the sample mean?

b. Construct an ungrouped frequency distribution.

c. Draw a histogram of this frequency distribution.

d. Use the frequency distribution and calculate the sample mean and standard deviation.

e. Determine the limits of the ¯ x  3s interval and mark this interval on the histogram.

f. The product specification limits are 11.7–12.3.

Does the sample indicate that production is within these requirements? Justify your answer.