ECON 15A Homework 1
Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit
ECON 15A
Homework 1
1. All highway bridges in the United States are inspected periodically for structural deficiency by
the Federal Highway Administration. Data from the FHWA 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.
Variable |
Quantitative |
Qualitative |
Length of maximum span (feet) |
|
|
Number of vehicle lanes |
|
|
Toll bridge (yes or no) |
|
|
Average daily traffic |
|
|
Condition of deck (good, fair, or poor) |
|
|
Bypass or detour length (miles) |
|
|
Route type (interstate, U.S. , state, county, or city) |
|
|
2. The 2007 NBI data were analyzed and the results made available at the FHWA Web site. Using the FHWA inspection ratings, each of the 599,766 highway bridges in the United States was categorized as structurally deficient, functionally obsolete, or safe. About 12% of the bridges were found to be structurally deficient, while 13.5% 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?
3. The employment status (employed or unemployed) of each individual in the U.S. workforce is a set of data that is of interest to economists, businesspeople, and sociologists. To obtain information about the employment status of the workforce, the U.S. Bureau of the Census conducts what is known as the Current Population Survey. Each month interviewers visit about 59,000 of the 98 million households in the United States and question the occupants over 14 years of age about their employment status. Their responses enable the Bureau of the Census to estimate the percentage of people in the labor force who are unemployed (the unemployment rate).
a. Define the population of interest to the Census Bureau.
b. B. What variable is being measured? Is it qualitative or quantitative?
c. Is the problem of interest to the Census Bureau descriptive or inferential?
4. Rising health-care costs are of major concern to Americans. A nationwide survey of 2,119 U.S. adults was conducted to elicit opinions on who is to blame for the rising costs? The next table summarized the responses to the question “When you think of the rising costs of health care, who do you think is most responsible?”
a. Compute the relative frequencies in each response category.
Most Responsible for Rising Health-Care Costs |
Number Responding |
Relative Frequency |
Insurance Companies |
869 |
|
Pharmaceutical companies |
339 |
|
Government |
338 |
|
Hospitals |
127 |
|
Physicians |
85 |
|
Other |
128 |
|
Not at all sure |
233 |
|
Total |
2,119 |
|
b. Construct a relative frequency bar graph for the data.
c. Convert the relative frequency bar graph into a Pareto Diagram.
d. Construct a pie chart.
5. In the following table the weights of 40 male students at State University are recorded to the nearest pound. Construct a histogram (manually).
138 |
164 |
150 |
132 |
144 |
125 |
149 |
157 |
146 |
158 |
140 |
147 |
136 |
148 |
152 |
144 |
168 |
126 |
138 |
176 |
163 |
119 |
154 |
165 |
146 |
173 |
142 |
147 |
135 |
153 |
140 |
135 |
161 |
145 |
135 |
142 |
150 |
156 |
145 |
128 |
2022-01-06