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About 102926 results. 1294 free access solutions
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| m102750 | The systolic blood pressure of individuals is thought to be related to both age and weight. For a random sample of 11 men, the following data were obtained:
(a) Generate summary statistics, including the mean and standard deviation of each variable compute the coefficient of variation for each variable. Relative to its mean, which variable has greatest spread of data values? Which variable has the smallest spread of data values relative to its mean?
(b) For each pair of variables, generate the sample correlation coeffi cient r. Compute the corresponding coefficient of determination r2. Which variable (other than x1) has the greatest influence (by itself) on x1? Would you say that both variables x2 and x3 show a strong influence on x1 ? Explain your answer. What percent of the variation in x1 can be explained by the corresponding variation in x2 ? Answer the same question for x3 .
(c) Perform a regression analysis with x1 as the response variable. Use x2 and x3 as explanatory variables. Look at the coeffi cient of multiple determination. What percentage of the variation in x1 can be explained by the corresponding variations in x2 and x3 taken together?
(d) Look at the coeffi cients of the regression equation. Write out the regression equation. Explain how each coeffi cient can be thought of as a slope. If age were held fixed, but a person put on 10 pounds, what would you expect for the corresponding change in systolic blood pressure? If a person kept the same weight b |
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| m102751 | The taxi and takeoff time for commercial jets is a random variable x with a mean of 8.5 minutes and a standard deviation of 2.5 minutes. Assume that the distribution of taxi and takeoff times is approximately normal. You may assume that the jets are lined up on a runway so that one taxies and takes off immediately after another, and that they take off one at a time on a given runway. What is the probability that for 36 jets on a given runway, total taxi and takeoff time will be
(a) Less than 320 minutes?
(b) More than 275 minutes?
(c) Between 275 and 320 minutes? |
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| m102752 | The technology consultancy Data- Genetics published the online document PIN analysis. In addition to analyzing PIN numbers, password trends were examined. Seven million all-numeric passwords were collected and yielded the following estimate of the probability distribution of the number of digits used in an all-numeric password.
a. Explain why the probabilities in the table provide only an estimate of the true probabilities.
b. Estimate the probability that an all-numeric password contains at least six digits. |
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| m102753 | The technology consultancy Data-Genetics published the online document PIN analysis. In addition to analyzing PIN numbers, passwords trends were examined. Seven million all-numeric passwords were collected and yielded the following estimate of the probability distribution of the number of digits used in an all-numeric password.
On average, approximately how many digits would you expect an allnumeric password to have? Explain your answer. |
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| m102754 | The Television Bureau of Advertising publishes a report titled TV Basics for the purpose of providing information to help advertisers make the most effective and efficient use of local and national spot television advertisements. The following table gives a percentage distribution for the location of a television set in the home.
Location ____________________________ Percentage
Living or Sitting Room .............................. 27
Master Bedroom ...................................... 24
Child or other bedroom .............................. 19
Den or Office ......................................... 14
Kitchen or Dining Room ............................ 5
Basement or Garage .................................. 5
Other room or storage ................................. 6
Suppose that a home television set is randomly selected. What is the probability that it is
a. Located in a bedroom?
b. Not located in a bedroom?
c. Located in the kitchen, dining room, basement, or garage? |
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| m102755 | The Times Higher Education "World University Rankings" presents global university performance tables to judge world class universities on the basis of teaching, research, knowledge transfer, and international outlook. The rankings employ 13 carefully calibrated performance indicators to provide comprehensive and balanced comparisons. The top 10 universities for 2012-2013 are as shown in the following table.
What type of data is presented in the
a. First column of the table?
b. Second column of the table?
c. Third column of the table? |
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| m102756 | The Tropical Cyclone Report, a publication of the National Hurricane Center, contains comprehensive information on each tropical cyclone, including synoptic history, meteorological statistics, casualties, and damages. A hurricane is a tropical cyclone with winds that have reached a constant speed of 74 miles per hour or more. During one year, there were 10 Atlantic basin hurricanes. Their maximum wind speeds, in miles per hour (mph), were as shown in the following table.
Consider these storms a population of interest. Obtain the following parameters for the maximum wind speeds. Use the appropriate mathematical notation for the parameters to express your answers.
a. Mean
b. Standard deviation
c. Median
d. Mode
e. IQR |
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| m102757 | The two F-values that divide the area under the curve into a middle 0.95 area and two outside 0.025 areas
Use Table VIII in Appendix A to find the required F-value(s) for an F-curve with df = (4, 8). |
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| m102758 | The two most commonly used scales for measuring temperature are the Fahrenheit and Celsius scales. If you let y denote Fahrenheit temperature and x denote Celsius temperature, you can express the relationship between those two scales with the linear equation y = 32 + 1.8x.
a. Determine b0 and b1.
b. Find the Fahrenheit temperatures corresponding to the Celsius temperatures −40◦, 0◦, 20◦, and 100◦.
c. Graph the linear equation y = 32 + 1.8x, using the four points found in part (b).
d. Apply the graph obtained in part (c) to estimate visually the Fahrenheit temperature corresponding to a Celsius temperature of 28◦. Then calculate that temperature exactly by using the linear equation y = 32 + 1.8x. |
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| m102759 | The United States Office of Personnel Management (OPM) manages the civil service of the federal government. Results from its annual Federal Employee Viewpoint Survey (FEVS) are used to measure employee satisfaction on several work aspects, including Job Satisfaction, Pay Satisfaction, Organization Satisfaction, and an overall measure of satisfaction referred to as Global Satisfaction. In each case a 100-point scale with higher values indicating greater satisfaction is used (OPM website, July 6, 2016). Scores for Global Satisfaction, Job Satisfaction, Pay Satisfaction, and Organization Satisfaction for a sample of 65 employees are provided in the DATAfile named Satisfaction.
a. Develop the estimated multiple regression equation that can be used to predict the Global Satisfaction score using the Job Satisfaction, Pay Satisfaction, and Organization Satisfaction scores.
b. Predict the overall Global Satisfaction score for an employee with a Job Satisfaction score of 72, a Pay Satisfaction score of 54, and an Organization Satisfaction score of 53. |
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| m102760 | The United States ranks ninth in the world in per capita chocolate consumption; the average American eats 9.5 pounds of chocolate annually (Forbes, July 22, 2015). Suppose you are curious whether chocolate consumption is higher in Hershey, Pennsylvania, the location of The Hershey Company s corporate headquarters. A sample of 36 individuals from the Hershey area showed a sample mean annual consumption of 10.05 pounds and a standard deviation of s - 1.5 pounds. Using α =.05, do the sample results support the conclusion that mean annual consumption of chocolate is higher in Hershey than it is throughout the United States? |
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| m102761 | The U.S. Census Bureau collects information about the ages of people in the United States. Results are published in Current Population Reports. a. Identify the variable and population under consideration.
b. A sample of six U.S. residents yielded the following data on ages (in years). Determine the median of these age data. Decide whether this descriptive measure is a parameter or a statistic, and use statistical notation to express the result.
c. By consulting the most recent census data, we found that the median age of all U.S. residents is 37.2 years. Decide whether that descriptive measure is a parameter or a statistic, and use statistical notation to express the result. |
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| m102762 | The U.S. Census Bureau collects information on the U.S. population by ancestry and region of residence and publishes the results in American Community Survey. According to that document, 18% of the population resides in the Northeast.
a. If ancestry and region of residence are not associated, what percentage of Americans of Irish ancestry would reside in the Northeast?
b. There are roughly 37 million Americans of Irish ancestry. If ancestry and region of residence are not associated, how many Americans of Irish ancestry would reside in the Northeast?
c. There are, in fact, 9.25 million Americans of Irish ancestry who reside in the Northeast. Given this information and your answer to part (b), what can you conclude? |
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| m102763 | The U.S. Census Bureau compiles census data on educational attainment of Americans. From the document Current Population Survey, we obtained the 2010 distribution of educational attainment for U.S. adults 25 years old and older. Here is that distribution.
Highest level Percentage
Not HS graduate........................12.9
HS graduate..............................31.2
Some college.............................16.8
Associate s degree........................9.1
Bachelor s degree.......................19.5
Advanced degree.......................10.5
A random sample of 500 U.S. adults (25 years old and older) taken this year gave the following frequency distribution.
Highest level Frequency
Not HS graduate..................45
HS graduate.....................163
Some college........................76
Associate s degree...............53
Bachelor s degree...............102
Advanced degree................61
Decide, at the 5% significance level, whether this year s distribution of educational attainment differs from the 2010 distribution. |
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| m102764 | The U.S. Census Bureau compiles information on money income of people by type of residence and publishes its finding in Current Population Reports. Independent simple random samples of people residing inside principal cities (IPC), outside principal cities but within metropolitan areas (OPC), and outside metropolitan areas (OMA), gave the following data on income level.
a. Identify the populations under consideration.
b. Identify the variable under consideration.
c. At the 5% significance level, do the data provide sufficient evidence to conclude that people residing in the three types of residence are nonhomogeneous with respect to income level? |
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| m102765 | The U.S. Census Bureau divides the states in the United States into nine divisions: East North Central (ENC), East South Central (ESC), Middle Atlantic (MAC), Mountain (MTN), New England (NED), Pacific (PAC), South Atlantic (SAC), West North Central (WNC), andWest South Central (WSC). The following table gives the divisions of each of the 50 states.
a. Identify the population and variable under consideration.
b. Obtain both a frequency distribution and a relative-frequency distribution of the divisions.
c. Draw a pie chart of the divisions.
d. Construct a bar chart of the divisions.
e. Interpret your results. |
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| m102766 | The U.S. Census Bureau publishes annual price figures for new mobile homes in Manufactured Housing Statistics. The prices of a sample of 250 new mobile homes have roughly a bell-shaped distribution with mean $63.3 thousand and standard deviation $7.9 thousand.
a. Fill in the blanks: Approximately 95% of the mobile homes in the sample have prices between $_____ thousand and $_____ thousand.
b. Fill in the blank: Approximately _____% of the mobile homes in the sample have prices between $39.6 thousand and $87.0 thousand.
c. Approximately how many mobile homes in the sample have prices between $55.4 thousand and $71.2 thousand? |
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| m102767 | The U.S. Census Bureau publishes data on housing units in American Housing Survey for the United States. The following table provides a frequency distribution for the number of rooms in U.S. housing units. The frequencies are in thousands.
Rooms __________________________ No. of units
1 ............................................ 601
2 ............................................ 1,404
3 ............................................ 11,433
4 ............................................ 23,636
5 ............................................ 30,440
6 ............................................ 27,779
7 ............................................ 17,868
8+ ........................................... 19,257
Compute the following conditional probabilities directly; that is, do not use the conditional probability rule. For a U.S. housing unit selected at random, determine
a. The probability that the unit has exactly four rooms.
b. The conditional probability that the unit has exactly four rooms, given that it has at least two rooms.
c. The conditional probability that the unit has at most four rooms, given that it has at least two rooms.
d. Interpret your answers in parts (a)-(c) in terms of percentages. |
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| m102768 | The U.S. Census Bureau publishes data on housing units in American Housing Survey for the United States. The following table provides a frequency distribution for the number of rooms in U.S. housing units. The frequencies are in thousands.
Rooms ______________________No. of units
1 ................................... 601
2 ................................... 1,404
3 ................................... 11,433
4 ................................... 23,636
5 ................................... 30,440
6 ................................... 27,779
7 ................................... 17,868
8+ .................................. 19,257
A U.S. housing unit is selected at random. Find the probability that the housing unit obtained has
a. Four rooms.
b. More than four rooms.
c. One or two rooms.
d. Fewer than one room.
e. One or more rooms. |
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| m102769 | The U.S. Census Bureau publishes data on housing units in American Housing Survey for the United States. The following table provides a frequency distribution for the number of rooms in U.S. housing units. The frequencies are in thousands.
Rooms ___________________________ No. of units
1 ............................................. 601
2 ............................................. 1,404
3 ............................................. 11,433
4 ............................................. 23,636
5 ............................................. 30,440
6 ............................................. 27,779
7 ............................................. 17,868
8+ ............................................. 19,257
For a U.S. housing unit selected at random, let
A = event the unit has at most four rooms,
B = event the unit has at least two rooms,
C = event the unit has between five and seven rooms, inclusive, and
D = event the unit has more than seven rooms.
Describe each of the following events in words, and determine the number of outcomes (housing units) that constitute each event.
a. (not A)
b. (A & B)
c. (C or D) |
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