Guilt in decision making. The effect of guilt emotion on how a decision maker focuses on the problem was investigated in the Journal osthnvioml Decision Making {January 2007). A total of 1.71 volunteer students participated in the experiment, where each was randomly assigned to one of three emotional states (guilt, anger, or neutral) through a reading/wriiing task. Immediately after the task, the students were presented with a decision problem (e.g., whether or not to spend money on repairing a very old car). The researchers found Iiiat a higher proportion of students in the guiltystate group chose to repair the car than those in the neutralstate and angerstate groups. a. Identify the population, sample, and variables measured for this study. b. Identify the data-collection method used. c. What inference was made by the researcher? d. In later chapters you will learn that the reliability of an inference is related to the size of the sample used. In addition to sample size, what factors might affect the reliability of the inference drawn in this study?I 1.30 Structurally deficient highway bridges. Refer to Exercise 1.290. The NBI data were analyzed and the results made available at the FHWA Web site (www.fhwa.dot.gov). Using the FHWA inspection ratings, each of the 608,272 highway bridges in the United States was categorized as structurally deficient, functionally obsolete, or safe. About 13.5% of the bridges were found to be structurally deficient, while 3.5% were functionally obsolete. a. What is the variable of interest to the researchers? b. Is the variable of part a quantitative or qualitative? c. Is the data set analyzed a population or a sample? Explain. d. How did the NBI obtain the data for the study?1.29 Inspection of highway bridges. All highway bridges in the United States are inspected periodically for structural deficiency by the Federal Highway Administration (FHWA). Data from the FI-IWA inspections are compiled into the National Bridge Inventory (NBI). Several of the nearly 100 variables maintained by the NBI are listed below. Classify each variable as quantitative or qualitative. a. Length of maximum span (feet) b. Number of vehicle lanes c. Toll bridge (yes or no) d. Average daily trafc e. Condition of deck (good, fair, or poor) f. Bypass or detour length (miles) g. Route type (interstate, U.S., state, county, or city)