Questions and Answers of Statistics For Engineering And The Sciences

In Environmental Science & Technology (Oct. 1993), scientists reported on a study of the transport and transformation of PCDD, a pollutant emitted from solid waste incineration, motor vehicles,
Recording electrical activity of the brain is important in clinical problems as well as in neurophysiological research. To improve the signal-to-noise ratio (SNR) in the electrical activity, it is
Polychlorinated biphenyls (PCBs), used in the manufacture of large electrical transformers and capacitors, are extremely hazardous contaminants when released into the environment. The Environmental
A company produces a fast drying rubber cement in 32-ounce aluminum cans. A quality control inspector is interested in testing whether the variance of the amount of rubber cement dispensed into the
Refer to Exercise 7.84 and the Analytical Chemistry (Dec. 15, 2009) study in which scientists used high-performance liquid chromatography to determine the amount of drug in a tablet. Recall that 25
Refer to the International Journal of Forest Engineering (July 1999) study of the attributes of forest access roads in Ireland, Exercise 7.110. Recall that the transient surface deflection
Refer to the Journal of Engineering for Gas Turbines and Power (Jan. 2005) study of gas turbines augmented with high-pressure inlet fogging, Exercise 8.39. Heat rate data (kilojoules per kilowatt per
Refer to Exercise 8.44. Recall that an Environmental Science & Technology study was conducted to compare the mean oxon/thion ratios at a California orchard under two weather conditions—foggy
Refer to the Journal of Food Engineering (Sep. 2013) study of the characteristics of fried sweet potato chips, Exercise 8.74. Recall that a sample of 6 sweet potato slices fried at 130º using a
An experiment was conducted to study the effect of reinforced flanges on the torsional capacity of reinforced concrete T-beams (Journal of the American Concrete Institute, Jan.–Feb. 1986). Several
Suppose we want to test Ho: σ12 = σ22versus Ha: σ12 ≠ σ22. Show that the rejection region given bywhere F depends on v1 = (n1 - 1)df and v2 = (n2 - 1) df, is equivalent to the rejection
Refer to the Journal of Marketing Research (Dec., 2011) study of shopping cart design, Exercise 8.41. Recall that design engineers want to know whether the mean choice of vice-over virtue score is
Use the results of Exercise 8.89 to show thatwhere F depends on numerator df = [(Sample size for numerator sample variance) - 1] and denominator df = [(sample size for denominator sample variance) -
Refer to the Composites Fabrication Magazine (Sept. 2004) study of the strength of fiber-reinforced polymer (FRP) composite materials, Exercise 7.100. Recall that 10 specimens of pultruded FRP strips
Refer to the Journal of Engineering for Gas Turbines and Power (Jan. 2005) study of three types of gas turbines augmented with high pressure inlet fogging, Exercise 8.39. Heat rate data (kilojoules
Refer to Example 8.13 and the comparison of electric and gas utility plants. The data on plant investment per delivered quad for 11 plants using electrical utilities and 16 plants using gas utilities
Refer to the Meteoritics (Mar. 1995) study of lunar soil evolution, Exercise 8.62. Recall that one theory is that the proportion p of lunar soil grains that are coated with dust and/or glass
Let y1, y2, y3, ..... yn represent a random sample of size n selected from a Poisson probability distribution with unknown mean λ. Let X represent the sum of the Poisson values, X = Σyi. Then
Let y1, y2, y3, ..... yn represent a random sample of size n selected from a normal probability distribution with unknown mean μ and variance σ2 = 1. Then the sample mean, y̅ , has a normal
The Journal of Biogeography (Dec. 2003) published a study of ants in Mongolia (Central Asia). Botanists placed seed baits at five sites in the Dry Steppe region and six sites in the Gobi Desert and
Refer to the Journal of Biogeography (Dec. 2003) study of ants in Mongolia (Central Asia), Exercise 8.98, where you compared the mean number of ants at two desert sites. Since the sample sizes were
The Journal of Professional Issues in Engineering Education and Practice (Apr. 2005) reported on the results of a 2005 survey of courses offered at undergraduate engineering programs. Of the 90
The European Journal of Engineering Education (Vol. 38, 2013) published a study of the feasibility of adding a general engineering program to a university’s specialized engineering programs (e.g.,
Wet samplers are standard devices used to measure the chemical composition of precipitation. The accuracy of the wet deposition readings, however, may depend on the number of samplers stationed in
According to a popular model of managerial behavior, the current state of automation in a manufacturing firm influences managers’ perceptions of problems of automation. To investigate this
Researchers at Purdue University compared human real-time scheduling in a processing environment to an automated approach that utilizes computerized robots and sensing devices (IEEE Transactions,
A problem that occurs with certain types of mining is that some by-products tend to be mildly radioactive and these products sometimes get into our fresh water supply. The EPA has issued regulations
The National Science Foundation, in a survey of 2,237 engineering graduate students who earned their PhD degrees, found that 607 were U.S. citizens; the majority (1,630) of the PhD degrees were
Refer to the U.S. Army Corps of Engineers study of contaminated fish in the Tennessee River (Alabama).a. Use a random number table to generate a random sample of n = 40 observations on DDT
In the manufacture of machinery, it is essential to utilize parts that conform to specifications. In the past, diameters of the ball bearings produced by a certain manufacturer had a variance of
Home solar heating systems can be categorized into two groups, passive solar heating systems and active solar heating systems. In a passive solar heating system, the house itself is a solar energy
Environmental Science & Technology (Oct. 1993) reported on a study of contaminated soil in The Netherlands. A total of 72 400-gram soil specimens were sampled, dried, and analyzed for the
Engineers periodically analyze water samples for various types of organic material. The total organic carbon (TOC) level was measured in water samples collected at two sewage treatment sites in
Merck Research Labs conducted an experiment to evaluate the effect of a new drug using the Single-T swim maze. Nineteen impregnated dam rats were captured and allocated a dosage of 12.5 milligrams of
Current technology uses X-rays and lasers for inspection of solder-joint defects on printed circuit boards (PCBs). (Quality Congress Transactions, 1986.) A particular manufacturer of laser-based
One feature of a user-friendly computer interface is a stacked menu display. Each time a menu item is selected, a submenu is displayed partially over the parent menu, thus creating a series of
Does competition between separate research and development (R&D) teams in the U.S. Department of Defense, working independently on the same project, improve performance? To answer this question,
The building specifications in a certain city require that the sewer pipe used in residential areas have a mean breaking strength of more than 2,500 pounds per lineal foot. A manufacturer who would
Researchers estimate that in a typical month, about 75 billion text messages are sent in the U.S. Text messaging on mobile devices (e.g., cell phones, smart phones) often requires typing in awkward
A report on dental patients with temporomandibular (jaw) joint dysfunction (TMD) was published in General Dentistry (Jan/Feb. 2004). A random sample of 60 patients was selected for an experimental
Each month, Mechanical Engineering surveys its readers with an online “Question of the Month.” One issue reported on the responses to the question, “Do you feel you know enough about the latest
Refer to the Journal of Astrophysics & Astronomy (Mar./Jun. 2003) study of redshifts in Quasi-Stellar Objects (QSOs), Exercise 10.4. Recall that simple linear regression was used to model the
Find r and r2. Find the correlation coefficient and the coefficient of determination for the sample data of each of the following exercises. Interpret your results.a. Exercise 10.7 b.
If the assumptions of Section 11.2 are satisfied, it can be shown that s2 is independent of β̂i, the least-squares estimator of βi. Use this fact, along with Theorems 11.1 and 11.2, to show
Refer to Exercise 6.62. Use the computer to generate a random sample of n = 100 observations from a distribution with probability densityRepeat the procedure 1,000 times and compute the sample mean
An experiment was conducted to investigate the effect of temperature (T) and pressure (P) on the yield y of a chemical. Each of the two factors, temperature and pressure, was held constant at two
An experiment was conducted to investigate the effect of extrusion pressure P and temperature at extrusion T on the strength y of a new type of plastic. Two plastic specimens were prepared for each
Refer to the Environmental Science & Technology (Jan. 2005) study of the reliability of a commercial kit to test for arsenic in groundwater, Exercise 11.24. Recall that you fit a first-order
Refer to the Lichen Radionuclide Baseline Research project to monitor the level of radioactivity in lichen, Exercise 2.15. Recall that University of Alaska researchers collected 9 lichen specimens
Tension-leg platforms (TLPs) are used for oil and gas exploration under deep-sea conditions. The reliability of TLPs under impulsive loading was assessed in Reliability Engineering and System Safety
The failure of a computer disk pack is considered to be an initial failure if it occurs prior to time t = α and a wear-out failure if it occurs after time t = β. Suppose the failure time
Refer to the Journal for Engineering for Industry (May 1993) study of deep hole drilling under drill chip congestion, Exercise 8.32. Test to determine whether the true standard deviation of drill
Refer to the Journal of Food Engineering (Sep., 2013) study of the characteristics of sweet potato chips fried at different temperatures, Exercise 7.75. Recall that a sample of 6 sweet potato slices
Refer to the National Snow and Ice Data Center (NSIDC) collection of data on the albedo of ice melt ponds, Exercise 7.80. The visible albedo values for a sample of 504 ice melt ponds located in the
Refer to the Environmental Geology (Vol. 58, 2009) simulation study of how far a block from a collapsing rock wall will bounce down a soil slope, Exercise 2.29. Rebound lengths (in meters) were
In addition to the traditional bachelor of engineering (BE) degree, many universities worldwide offer a bachelor of technology (BTech) degree for students who wish to work as an engineering
Refer to the Oil & Gas Journal (Jan. 3, 2005) study of 3,400 oil and gas structures in the Gulf of Mexico, Exercise 3.19. The accompanying table breaks down these structures by type (caisson,
The results of an evaluation of the drinking water quality in Pakistan was reported in Drinking Water Engineering and Science (Vol. 6, 2013). Due to high levels of fluoride in the drinking water,
Refer to the Journal of Chemical Ecology (March 2013) study to determine the effectiveness of pheromones produced by two different strains of fall armyworms, Exercise 7.68. Recall that both
Refer to the Environmental Science & Technology (Jan. 2005) study of methyl tert-butyl ether (MTBE) contamination in New Hampshire wells, Exercise 7.66. Recall that 223 wells were classified
National Science Education Standards recommend that all life science students be exposed to methods of identifying unknown biological specimens. Due to certain limitations of traditional
Researchers at the University of Rochester studied the friction that occurs in the paper-feeding process of a photocopier (Journal of Engineering for Industry, May 1993). The experiment involved
A wiki is a web information depository with content that can be updated and edited through a web browser. Engineering faculty at a university in Portugal investigated the degree to which wiki tools
Refer to the Process Safety Progress (Sept. 2004) study of an emergency response system for incidents involving toxic chemicals in Taiwan, Exercise 3.5. In a sample of 250 toxic chemical incidents
The Computer Security Institute (CSI) conducts an annual survey of computer crime at United States businesses. CSI sends survey questionnaires to computer security personnel at all U.S. corporations
In AlChE Journal (Jan. 2005), chemical engineers published a new method for modeling multicomponent transport of gases. Twelve gas mixtures consisting of neon, argon, and helium were prepared at
Civil engineers at West Virginia University have developed a 3D model to predict the response of jointed concrete pavement to temperature variations. (The International Journal of Pavement
Refer to the IEICE Transactions on Information & Systems (Jan. 2005) comparison of two methods of testing electronic circuits, Exercise 7.52. Each of 11 circuits was tested using the standard
Refer to the Environmental & Engineering Geoscience (Nov. 2012) study of methods for predicting settlement of shallow foundations on cohesive soil, Exercise 7.50. Actual settlement values for a
Refer to the Exploration and Mining Geology (Vol. 18, 2009) study of drilling twin holes, Exercise 7.49. Recall that geologists use data collected at both holes to estimate the total amount of heavy
Refer to the Journal of Computer-Mediated Communication (Apr. 2004) study to compare relational intimacy in people interacting via computer-mediated communication (CMC) to people meeting face-to-face
Environmental Science & Technology (Oct. 1993) reported on a study of insecticides used on dormant orchards in the San Joaquin Valley, California. Ambient air samples were collected and analyzed
In Ecological Engineering (Feb. 2004), the potential of floating aquatic plants to treat dairy manure wastewater was investigated. For one part of the study, 16 treated wastewater samples were
Computer mediated communication (CMC) is a form of interaction that heavily involves technology (e.g., instant messaging, email). A study was conducted to compare relational intimacy in people
Refer to the Journal of Marketing Research (Dec., 2011) study of shopping cart design, Exercise 2.43. Design engineers want to know whether you may be more likely to purchase a vice product (e.g., a
Refer to the Harris Corporation/ University of Florida comparison of the mean process voltage readings at two locations, Exercise 7.46. The data for 30 production runs at both the old and new
Refer to the Journal of Engineering for Gas Turbines and Power (Jan. 2005) study of gas turbines augmented with high-pressure inlet fogging, Exercise 8.29. The researchers classified gas turbines
Refer to the Journal of Agricultural, Biological, and Environmental Sciences (June 2005) analysis of the Index of Biotic Integrity (IBI), Exercise 7.42. Recall that the IBI measures the biological
When asked, “How much time will you require to complete this task”, cognitive theory posits that people (e.g., an electrical engineer) will typically underestimate the time required. Would the
Refer to Exercise 7.39 and the Analytical Chemistry (Dec. 15, 2009) study in which scientists used high-performance liquid chromatography to determine the amount of drug in a tablet. Recall that 25
Refer to Exercises 8.8–8.10. Show that the rejection region for the likelihood ratio test is given by Z > zα,where P(Z > zα) = α. Under the assumption that HO: μ = 0 is true, show that
”Deep hole” drilling is a family of drilling processes used when the ratio of hole depth to hole diameter exceeds 10. Successful deep hole drilling depends on the satisfactory discharge of the
When people get lost in unfamiliar terrain, do they really walk in circles, as is commonly believed? To answer this question, researchers conducted a field experiment and reported the results in
In Exercise 5.36 you learned that the mean alkalinity level of water specimens collected from the Han River in Seoul, Korea, is 50 milligrams per liter. (Environmental Science & Engineering,
The level of dissolved oxygen in the surface water of a lake is vital to maintaining the lake’s ecosystem. Environmentalists from the University of Wisconsin monitored the dissolved oxygen levels
Refer to the American Journal of Physical Anthropology (Vol. 142, 2010) study of the characteristics of cheek teeth (e.g., molars) in an extinct primate species, Exercise 2.14. Recall that the
To protect against earthquake damage, steel beams are typically fitted and connected with plastic hinges. However, these plastic hinges are prone to deformations and are difficult to inspect and
In countries with a water shortage, converting salt water to potable water is a critical problem. The standard method of water distillation is with a single slope solar still. Several enhanced solar
Refer to the Anti-corrosion Methods and Materials (Vol. 50, 2003) study of the surface roughness of coated interior pipe used in oil fields, Exercise 7.26. The data (in micrometers) for 20 sampled
An analyst tested the null hypothesis μ ≥ 20 against the alternative hypothesis that μ < 20. The analyst reported a p-value of .06. What is the smallest value of α for which the null
For a large-sample test of Ho: θ = θo versus Ha: θ ≠ θo, compute the p-value associated with each of the following test statistic values:a. z = -1.01b. z = -2.37c. z = 4.66d. z = 1.45
Explain why each of the following statements is incorrect:a. The probability that the null hypothesis is correct is equal to α.b. If the null hypothesis is rejected, then the test proves that the
Pharmaceutical companies are continually searching for new drugs. Testing the thousands of compounds for the few that might be effective is known in the pharmaceutical industry as drug screening.
Pascal is a high-level programming language used frequently in microprocessors. An experiment was conducted to investigate the proportion of Pascal variables that are array variables (in contrast to
A manufacturer of power meters, which are used to regulate energy thresholds of a data communications system, claims that when its production process is operating correctly, only 10% of the power
Refer to Exercise 8.8. Suppose we want to test Ho: μ = 0 against the alternative Ha: μ > 0. Since the estimator of μ is µ̂ = y̅, the likelihood ratio test statistic isShow thatUse the fact
Industrial engineers want to compare two methods of real-time scheduling in a manufacturing operation. Specifically, they want to determine whether the mean number of items produced differs for the
For a large-sample test of Ho: θ = θo versus Ha: θ > θo, compute the p-value associated with each of the following test statistic values:a. z = 1.96b. z = 1.645c. z = 2.67d. z = 1.25
The Environmental Protection Agency wishes to test whether the mean amount of radium-226 in soil in a Florida county exceeds the maxium allowable amount, 4 pCi/L.
Each year, Computerworld magazine reports the Datapro ratings of all computer software vendors. Vendors are rated on a scale from 1 to 4 (1 = poor, 4 = excellent) in such areas as reliability,

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