Mechanics and Techniques Problems

6.1. Consider the summarized frequency data found in file C06 Deliveries.xls [.rda]. This shows data on the unloading times for trucks at StateEx, both broken down by truck type (Semi or Van) and overall.

1. Estimate the average unloading time for semis, vans, and overall.
2. Estimate the standard deviation of the loading times for semis, vans, and overall.
3. Create a histogram of the overall unloading times. Mark the location of the mean on the histogram and add six additional markers to show the location for one, two and three standard deviations both above and below the mean. Where do the average unloading times for the semis fall? What about the vans?

6.2. EverythingRUs is an extremely diversified company, manufacturing and distributing goods as well as providing a variety of services. The table below shows the mean monthly revenue and mean monthly cost for each sector of the company, along with the percentage each sector occupies in the overall revenue and cost structure. Use this information to estimate the mean monthly revenue and mean monthly cost for the entire company. All revenue and cost figures are in thousands of dollars.

6.3. Match the histograms below with their cumulative distributions shown in figure 6.10. The graphs in the left-hand column (labeled A - D) are histograms. The graphs in the right-hand column (labeled E - H) are cumulative distributions. Each histogram contains the same number of total observations. The cumulative distributions are given by percentage of total, rather than actual count.

Figure 6.10: Match the histograms (A - D) with the cumulative distributions (E - H) in problem 3.

6.4. Match the histograms (labeled A - D) below with the boxplot (labeled 1 - 4) in figure 6.11 that best matches the data.

Figure 6.11: Match the histograms (A - D) with the cumulative distributions (E - H) in problem 4.