Questions and Answers of Statistics For Engineering And The Sciences

The Journal of Human Stress (Summer 1987) reported on a study of “psychological response of firefighters to a chemical fire.” The researchers used multiple regression to predict emotional
Refer to the Environmental Science & Technology study of sorption of organic vapors, Exercise 12.7. Consider modeling the vapor retention coefficient y as a function of one of the two
The Journal of Space Engineering (Vol. 4, 2011) investigated the properties of large, deployable space membranes used to store structures such as solar sails, antennas, sunshields, and solar power
A study of the atmospheric pollution on the slopes of the Blue Ridge Mountains (Tennessee) was conducted. The file LEADMOSS contains the levels of lead found in 70 fern moss specimens (in micrograms
Refer to the Human Factors study of the performance of a computerized speech recognizer, Exercise 12.26. Recall that the researchers built a complete second-order model for task completion time (y)
An experiment was conducted to evaluate the performances of a diesel engine run on synthetic (coal-derived) and petroleum-derived fuel oil (Journal of Energy Resources Technology, Mar. 1990). The
Many cognitively demanding jobs (e.g., air traffic controller, radar/sonar operator) require efficient processing of visual information. Researchers at Georgia Tech investigated the variables that
Oil wells can suffer from scale deposits, leading to a reduction in well flow performance. Consequently, it is important for oil well managers to periodically assess the damage caused by scale
A trade-off study regarding the inspection and test of transformer parts was conducted by the quality department of a major defense contractor. The investigation was structured to examine the effects
In increasingly severe oil well environments, oil producers are interested in high-strength nickel alloys that are corrosion-resistant. Since nickel alloys are especially susceptible to hydrogen
Refer to Exercise 14.8. Use Bonferroni’s method to compare the mean heat rates of the three gas turbine engines. Use α = .06.Data from Exercise 14.8Refer to the Journal of Engineering for Gas
Refer to Exercise 14.11. Use a multiple comparisons procedure to compare the mean Al/Be ratios for the five boreholes. Identify the means that appear to differ. Use α = .05.Data from Exercise
Refer to the Behavioral Neuroscience (Feb. 2004) study of the drug scopolamine’s effects on memory for word-pair associates, Exercise 14.13. Recall that the researchers theorized that the mean
Refer to Exercise 14.19. Use a multiple comparisons procedure to compare the mean crack widths for the four wetting periods. Identify the means that appear to differ. Use α = .05.Data from Exercise
In Ecological Engineering (Feb. 2004), a new methodology for tree seedling production (called aqua-forest system) was compared to a conventional tree nursery method. The new method was applied to
Construct an R-chart for the data of Exercise 16.15. Does the process variation appear to be in control?Data from Exercise 16.15Refer to the manufacture of a rheostat knob, Exercise 16.7. To monitor
A quality control inspector is studying the alternative sampling plans (n = 5, a = 1) and (n = 25, a = 5).a. Sketch the operating characteristic curves for both plans, using lot fractions defective
An experiment was conducted to investigate the sheet flow rate of a land waste treatment plant. Classify each of the following independent variables as quantitative or qualitative and describe the
Environmental Science & Technology (Oct. 1993) published an article that investigated the variables that affect the sorption of organic vapors on clay minerals. The independent variables and
The accompanying graphs depict pth-order polynomials for one quantitative independent variable.a. For each graph, identify the order of the polynomial. b. Using the parameters β0, β1, β2,
Graph the following polynomials and identify the order of each on your graph:a. E(y) = 2 + 3xb. E(y) = 2 + 3x2c. E(y) = 1 + 2x + 2x2 + x3d. E(y) = 2x + 2x2 + x3e. E(y) = 2 - 3x2f. E(y) = -2 + 3x
The amount of pressure used to produce a certain plastic is thought to be related to the strength of the plastic. Researchers believe that, as pressure is increased, the strength of the plastic
The lane utilization of a highway is measured by how the traffic flow in one direction is distributed among the available lanes. A lane utilization model for highways in the United Kingdom was
The level of overcrowding for passengers waiting at a train station was investigated in the Journal of Transportation Engineering (June 2013). The researchers measured “crowdedness” as the
Does exercise improve the human immune system? An experiment was conducted by a physiologist at the University of Florida to determine whether such a relationship exists. Thirty subjects volunteered
The National Snow and Ice Data Center at the University of New Hampshire collected data on the temperature of ice core samples from a glacier snow pit. The ice core samples were collected from depths
Suppose the true relationship between E(y) and the quantitative independent variables x1 and x2 is described by the following first-order model:E(y) = 4 - x1 + 2x2a. Describe the corresponding
Suppose the true relationship between E(y) and the quantitative independent variables x1 and x2 is E(y) = 4 - x1 + 2x2 + x1x2 Answer the questions posed in Exercise 12.16. Explain the
Refer to the Environmental Science & Technology study of sorption of organic vapors, Exercise 12.7. Consider modeling the retention coefficient y as a function of bothx1 = Temperature (degrees)x2
A Harvard University biologist used multiple regression to model the swimming speed of an American eel. (Proceedings of the Royal Society, B, Dec. 2004.) Steady swimming speed, y (body lengths per
Refer to the Journal of Transportation Engineering (May 2013) study of the lane utilization of a highway, Exercise 12.13. Recall that the dependent variable in the analysis was lane utilization y,
Research in the International Journal of Foresting Engineering (Vol. 19, 2008) investigated the muscle activity patterns in the neck and upper extremities exhibited during a work day among forestry
Data on the polysilicon thickness of semiconductor wafers processed using rapid thermal chemical vapor deposition was analyzed in the Journal of the American Statistical Association (March 1998). The
An exploration seismologist wants to develop a model that will allow him to estimate the average signal-to-noise ratio of an earthquake’s seismic wave, y, as a function of two independent
A study reported in Human Factors (Apr. 1990) investigated the effects of recognizer accuracy and vocabulary size on the performance of a computerized speech recognition device. Accuracy (x1) of the
Refer to the Engineering Project Organizational Journal (Vol. 3., 2013) study of how the emotional intelligence of individual team members relates directly to the performance of their team, Exercise
Refer to the Engineering Structures and Technologies (Sep. 2012) study on the use of processed straw as thermal insulation for homes, Exercise 11.4. You used data on n = 25 straw specimens (see right
Suppose you want to use the coding system for observational data to fit a second-order model to the tire pressure–automobile mileage data given in the next table below.a. Give the equation relating
Refer to the Journal of Transportation Engineering (June 2013) study of overcrowding at a train station, Exercise 12.14. Using data collected for a sample of 20 train stops (see below), you analyzed
Refer to the IHS Journal of Hydraulic Engineering (September 2012) study of the repair and replacement of water pipes, Exercise 11.37. Recall that a team of civil engineers used regression analysis
Refer to the Journal of Agricultural, Biological, and Environmental Statistics (March 2005) study of the chemical composition of rainwater, Exercise 12.1. Recall that the nitrate concentration, y
Refer to the Journal of Human Stress study of firefighters, Exercise 12.5. Consider using the qualitative variable, level of social support, as a predictor of emotional stress y. Suppose that four
Refer to the Environmental Science & Technology study of sorption of organic vapors, Exercise 12.7. Consider using the qualitative variable, organic compound, as a predictor of the retention
Refer to the International Journal of Foresting Engineering (Vol. 19, 2008) study of neck muscle activity patterns among forestry vehicle operators, Exercise 12.23. Recall that the researchers
An electrical engineer wants to compare the mean life lengths (in hours) of five different brands of magnetron tubes. Data are gathered on 10 magnetron tubes selected at random from each of the
Because of the hot, humid weather conditions in Florida, the growth rates of beef cattle and the milk production of dairy cows typically decline during the summer. However, agricultural and
Evolutionary Ecology Research (July 2003) published a study of the patterns of extinction in the New Zealand bird population. The NZBIRDS file contains qualitative data on flight capability (volant
Wastewater treatment systems are designed to maintain the chemical, physical, and biological integrity of water. These systems, however, tend to generate various greenhouse gases, such as methane
Corporate sustainability refers to business practices designed around social and environmental considerations (e.g., “going green” and energy conservation). Business and Society (March 2011)
Refer to the Environmental Science & Technology study of sorption of organic vapors, Exercise 12.7. The independent variables used to model the retention coefficient y arex1 = Temperature
Refer to the International Journal of Foresting Engineering (Vol. 19, 2008) study of neck muscle activity patterns among forestry vehicle operators, Exercises 12.23 and 12.36. Recall that the
Eli Lilly and Company has developed three methods (G, R1, and R2) for estimating the shelf life of its drug products based on the potency of the drug.* One way to compare the three methods is to
An experiment was conducted to compare four Web browsers on their ability to display graphics. (Journal of Graphic Engineering Design, Vol. 3, 2012.) The four browsers were the latest versions of
Refer to the Journal of the Institute of Engineering (Vol. 8, 2011) study of methane gas (milligrams per liter) emitted from wastewater treatment sludge, Exercise 12.42. Recall that two different
Refer to the International Journal of Foresting Engineering (Vol. 19, 2008) study of neck muscle activity patterns among forestry vehicle operators, Exercise 12.23. Recall that the researchers
Refer to the Journal of the Institute of Engineering (Vol. 8, 2011) study of methane gas (milligrams per liter) emitted from wastewater treatment sludge, Exercises 12.42 and 12.51. Recall that two
The American Educational Research Journal (Fall 1998) published a study of students’ perceptions of their science ability in hands-on classrooms. A first-order, main effects model that was used to
Refer to the Journal of Colloid and Interface Science study of water/oil mixtures, Exercise 11.27. Recall that three of the seven variables used to predict voltage (y) were volume (x1), salinity
Refer to Exercise 12.25, in which an exploration seismologist wants to develop a regression model for estimating the mean signal-to-noise ratio of seismic waves from earthquakes. The model under
Refer to the Journal of Human Stress study of firefighters, Exercise 12.5. It is thought that a complete second-order model, shown here, will be adequate to describe the relationship between
Refer to the Environmental Science & Technology study of sorption of organic vapors, Exercise 12.45. Consider using the quantitative variable, relative humidity, and the qualitative variable,
A building materials engineer is experimenting with three different cement mixes—dry, damp, and wet—for laying concrete. Since the compressive strength of a concrete slab varies as a function of
An operations manager is interested in modeling E(y), the expected length of time per month (in hours) that a machine will be shut down for repairs, as a function of the type of machine (001 or 002)
There are six independent variables, x1, x2, x3, x4, x5, and x6, that might be useful in predicting a response y. A total of n = 50 observations are available, and it is decided to employ stepwise
Fossilized human footprints provide a direct source of information on the gait dynamics of extinct species. How paleontologists and anthropologists interpret these prints, however, may vary. To gain
A marine biologist was hired by the EPA to determine whether the hot-water runoff from a particular power plant located near a large gulf is having an adverse effect on the marine life in the area.
Refer to the International Journal of Foresting Engineering (Vol. 19, 2008) study of neck muscle activity patterns among forestry vehicle operators, Exercise 12.23. Recall that the researchers
Periodically, software engineers must provide estimates of their effort in developing new software. In the Journal of Empirical Software Engineering (Vol. 9, 2004), multiple regression was used to
Air pollution regulations for power plants are often written so that the maximum amount of pollution that can be emitted increases as the plant’s output increases. Assuming this is true, write a
An engineer has proposed the following model to describe the relationship between the number of acceptable items produced per day (output) and the number of work-hours expended per day (input) in a
Many service stations offer self service gasoline at reduced prices when customers pay with cash rather than credit. Suppose an oil company wants to model the mean monthly gasoline sales, E(y), of
Refer to The Astronomical Journal (July 1995) study of quasars detected by a deep space survey, Exercise 11.72. Recall that several quantitative independent variables were used to model the quasar
Refer to the Statistics in Action problem for this chapter. Recall that we built a model for y = natural logarithm of supply price for an intrastate trucking shipment as a function of the following
A 40-year-old masonry duplex structure has recently undergone a passive solar retrofit with features including insulated exterior walls, heat distribution systems, storm sashes, and air-lock entries.
A company is studying three different safety programs, A, B, and C, in an attempt to reduce the number of work-hours lost because of accidents. Each program is to be tried at three of the company’s
A field experiment was conducted to assess the effect of organic enrichment on the mean density of mosquito larvae. (Journal of the American Mosquito Control Association, June 1995.) Larval specimens
Refer to the American Scientist (Jul–Aug. 1998) study of the relationship between number of self avoiding and unrooted walks, Exercise 11.71. The data for the analysis are repeated in the
The dissolved oxygen content, y, in rivers and streams is related to the amount, x1, of nitrogen compounds per liter of water and the temperature, x2, of the water. Write the complete second-order
When the U.S. airline industry was deregulated, researchers have questioned whether the deregulation has ensured a truly competitive environment. If so, the profitability of any major airline would
A firm has developed a new type of halogen lightbulb and is interested in evaluating its performance to decide whether to market the bulb. It is known that the level of light output of the bulb
In a designed experiment, a. What two factors affect the quantity of information?b. How does blocking increase the quantity of information?
According to a University of Florida researcher, the longer a beachgoers sits in wet sand or stays in the water, the higher the risk of gastroenteritis (University of Florida News, Jan. 29, 2008).
Refer to the Journal of Articles in Support of the Null Hypothesis (Vol. 6, 2009) study to determine whether video game players have superior visual attention skills over non-video game players,
Applied Animal Behaviour Science (October 2000) published a study of the taste preferences of caged cockatiels. A sample of birds bred at the University of California, Davis, was randomly divided
A University of South Florida clinical trial of 50,000 smokers was carried out to compare the effectiveness of CT scans with X-rays for detecting lung cancer. (Today’s Tomorrows, Fall 2002.) Each
Refer to the randomized block design setup to compare the mean costs estimated by four DOT engineers, Examples 13.2 and 13.3.a. Write the model for each observation of estimated cost y for engineer
The Electronic Journal of Biotechnology (Dec. 15, 2003) published an article on a comparison of two yeast extracts, baker’s yeast and brewer’s yeast. Brewer’s yeast is a surplus by-product
Human Factors (December 2009) investigated whether back and knee strength dictates the load lifting strategies of males and females. A sample of 32 healthy adults (16 men and 16 women) participated
Factorial models.a. Write the complete factorial model for a 2 × 3 factorial experiment where both factors are qualitative.b. Write the complete factorial model for a 2 × 3 × 3 factorial
Consider a factorial design with two factors, A and B, each at three levels. Suppose we select the following treatment (factor–level) combinations to be included in the experiment: A1B1, A2B1,
Suppose you wish to investigate the effect of three qualitative factors on a response y.a. Explain why a factorial selection of treatments is better than varying each factor, one at a time, while
Why is replication important in a complete factorial experiment?
Consider a 2 × 2 factorial. How many replications are required to estimate the interaction β to within two units with a 95% confidence interval? Assume that the standard deviation of the response
For a randomized block design with b blocks, the estimated standard error of the estimated difference between any two treatment means is √2/b. Use this formula to determine the number of blocks
How do you measure the quantity of information in a sample that is pertinent to a particular population parameter?
What steps in the design of an experiment affect the volume of the signal pertinent to a particular population parameter?
In what step in the design of an experiment can you possibly reduce the variation produced by extraneous and uncontrolled variables?
Explain the difference between a completely randomized design and a randomized block design. When is a randomized block design more advantageous?
Consider a two-factor factorial experiment where one factor is set at two levels and the other factor is set at four levels. How many treatments are included in the experiment? List them.
Write the complete factorial model for a 2 × 2 × 4 factorial experiment where both factors at two levels are quantitative and the third factor at four levels is qualitative. If you conduct one

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