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| m102770 | The U.S. Census Bureau publishes data on the population of the United States by race and Hispanic origin in American Community Survey. From that document, we constructed the following bar chart. Note that people who are Hispanic may be of any race, and people in each race group may be either Hispanic or not Hispanic.
a. Explain why a break is shown in the first bar.
b. Why was the graph constructed with a broken bar?
c. Is this graph potentially misleading? Explain your answer. |
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| m102771 | The U.S. Census Bureau tracks sales per month for various products and services through its Monthly Retail Trade Survey. Figure shows monthly bookstore sales in millions of dollars for 2014.
a. Are the data quantitative or categorical?
b. Are the data cross-sectional or time series?
c. Which month has the highest sales?
d. Which month has the second highest sales?
e. Why do you think the answers to parts (c) and (d) might be the two highest months? Explain. |
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| m102772 | The U.S. Congress, Joint Committee on Printing, provides information on the composition of Congress in Congressional Directory. Here is a joint probability distribution for the members of the 113th Congress by legislative group and political party. The "other" category includes Independents and vacancies. (Rep = Representative.)
a. Determine P(P1), P(C2), and P(P1 & C2).
b. Use the special multiplication rule to determine whether events P1 and C2 are independent. |
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| m102773 | The U.S. Department of Agriculture collects data pertaining to the value of agricultural exports and publishes its findings in U.S. Agricultural Trade Update. For one year, the values of these exports, by state, are provided on the WeissStats site. Data are in millions of dollars.
a. Identify the population and variable under consideration.
b. Use the technology of your choice to obtain and interpret a frequency histogram, a relative-frequency histogram, or a percent histogram of the data.
c. Use the technology of your choice to obtain a dotplot of the data.
d. Use the technology of your choice to obtain a stem-and-leaf diagram of the data.
e. Identify the modality and symmetry (or nonsymmetry) of the distribution.
f. If the distribution is unimodal and nonsymmetric, state whether it is right skewed or left skewed. |
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| m102774 | The U.S. Department of Agriculture publishes information about U.S. farms in Census of Agriculture. A joint frequency distribution for number of farms, by acreage and tenure of operator, is provided in the following contingency table. Frequencies are in thousands.
a. Fill in the six missing entries.
b. How many cells does this contingency table have?
c. How many farms have under 50 acres?
d. How many farms are tenant operated?
e. How many farms are operated by part owners and have between 500 and 1000 acres?
f. How many farms are not full-owner operated?
g. How many tenant-operated farms have 180 acres or more? |
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| m102775 | The U.S. Department of Agriculture publishes information about U.S. farms in Census of Agriculture. A joint frequency distribution for number of farms, by acreage and tenure of operator, is provided in the following contingency table. Frequencies are in thousands.
a. Fill in the six missing entries.
b. How many cells does this contingency table have?
c. How many farms have under 50 acres?
d. How many farms are tenant operated?
e. How many farms are operated by part owners and have between 500 acres and 999 acres, inclusive?
f. How many farms are not full-owner operated?
g. How many tenant-operated farms have 180 acres or more? |
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| m102776 | The U.S. Department of Agriculture reports in Food Consumption Prices, and Expenditures that the average American consumed about 33.5 lb of cheese in 2011. Cheese consumption has increased steadily since 1960, when the average American ate only 8.3 lb of cheese annually. The following table provides last year s cheese consumption, in pounds, for 35 randomly selected Americans. Use limit grouping with a first class of 20-22 and a class width of 3.
a. Determine a frequency distribution.
b. Obtain a relative-frequency distribution.
c. Construct a frequency histogram based on your result from part (a).
d. Construct a relative-frequency histogram based on your result from part (b). |
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| m102777 | The U.S. Department of Defense collects data on active members in the National Guard. Results are published in Selected Manpower Statistics. According to that document, 77.0% of members are in the Army National Guard and 10.2% of members are Black and in the Army National Guard. What percentage of members in the Army National Guard are Black? |
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| m102778 | The U.S. Department of Defense collects various data on military personnel. The following contingency table provides a joint frequency distribution for marital status and pay grade of active Naval military during one year. Pay grades are divided into three groups: Enlisted, Officer, and Warrant Officer, and are used to determine a military member s entitlements.
For the active Naval military personnel during the year in question,
a. Fill in the five missing entries.
b. How many are officers?
c. How many are enlisted and have a civilian marriage?
d. How many are either enlisted or have a civilian marriage?
e. How many are neither enlisted nor have a civilian marriage?
f. How many do not have a joint service marriage? |
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| m102779 | The U.S. Department of Housing and Urban Development compiles information on new, privately owned single family houses. According to the document Characteristics of New Housing, in 2012 the mean floor space of such homes was 2505 sq ft and the median was 2306 sq ft. Which measure of center do you think is more appropriate? Justify your answer. |
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| m102780 | The U.S. Department of Justice examined all reported cases of identity theft for U.S. residents aged 16 or older. Their data show that of all the reported incidents of identity theft in a recent year, 40% involved existing credit card accounts. You are to design a simulation of seven reported identity thefts showing which ones involve existing credit card accounts and which ones do not. How would you assign the random digits 0 through 9 to the two categories "Does" and "Does not" involve existing credit card accounts? Use your random-digit assignment and the random-number table to generate the results from a random sample of seven identity thefts. If you do the simulation again, do you expect to get exactly the same results? |
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| m102781 | The U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics provides information on prison sentences in the document National Corrections Reporting Program. A random sample of 20 maximum sentences for murder yielded the data, in months, presented on the Weiss Stats site. Use the technology of your choice to do the following.
a. Find a 95% confidence interval for the mean maximum sentence of all murders. Assume a population standard deviation of 30 months.
b. Obtain a normal probability plot, boxplot, histogram, and stemand- leaf diagram of the data.
c. Remove the outliers (if any) from the data, and then repeat part (a).
d. Comment on the advisability of using the z-interval procedure on these data. |
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| m102782 | The U.S. Geological Survey compiled historical data about Old Faithful Geyser (Yellowstone National Park) from 1870 to 1987. Some of these data are published in the book The Story of Old Faithful, by G. D. Marler (Yellowstone Association Press). Let x1 be a random variable that represents the time interval (in minutes) between Old Faithful s eruptions for the years 1948 to 1952. Based on 9340 observations, the sample mean interval was x̅1 = 63.3 minutes. Let x2 be a random variable that represents the time interval in minutes between Old Faithful s eruptions for the years 1983 to 1987. Based on 25,111 observations, the sample mean time interval was x̅2 = 72.1 minutes. Historical data suggest that (1 = 9.17 minutes and (2 = 12.67 minutes. Let m1 be the population mean of x1 and let (2 be the population mean of x2.
(a) Check Requirements Which distribution, normal or Student s t, do we use to approximate the x̅1 - x̅2 distribution? Explain.
(b) Compute a 99% con fidence interval for (1 - (2.
(c) Interpretation Comment on the meaning of the con fidence interval in the context of this problem. Does the interval consist of positive numbers only? negative numbers only? a mix of positive and negative numbers? Does it appear (at the 99% confi dence level) that a change in the interval length between eruptions has occurred? Many geologic experts believe that the distribution of eruption times of Old Faithful changed after the major earthquake that occurred in 1959. |
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| m102783 | The U.S. Geological Survey monitors and reports on earthquakes, providing daily real-time, worldwide earthquake lists. Some of the information for four of the 105 earthquakes that occurred on May 10, 2013, is shown in the following table. Magnitude is given on the Richter scale and NST stands for the number of stations that reported the activity on the same earthquake.
Identify the type of data provided by the information in the
a. First column of the table.
b. Second column of the table.
c. Third column of the table.
d. Fourth column of the table.
e. Fifth column of the table. |
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| m102784 | The U.S. government s flagship international educational exchange program, the Fulbright program, is sponsored by the Bureau of Educational and Cultural Affairs. Fulbrights are awarded based on "academic and leadership potential, providing the opportunity to exchange ideas and contribute to finding solutions to shared international concerns." For 2012-2013, the top 10 doctoral/research institutions receiving Fulbright awards are as shown in the following table. The success rate gives the number of grants per application, expressed as a percentage. Identify the type of data provided by the information in each column of the table. |
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| m102785 | The U.S. National Oceanic and Atmospheric Administration publishes temperature data in Climatography of the United States. According to that document, the annual average maximum and minimum temperatures for selected cities in the United States are as provided on the WeissStats site.
a. Identify the population and variable under consideration.
b. Use the technology of your choice to obtain and interpret a frequency histogram, a relative-frequency histogram, or a percent histogram of the data.
c. Use the technology of your choice to obtain a dotplot of the data.
d. Use the technology of your choice to obtain a stem-and-leaf diagram of the data.
e. Identify the modality and symmetry (or nonsymmetry) of the distribution.
f. If the distribution is unimodal and nonsymmetric, state whether it is right skewed or left skewed. |
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| m102786 | The U.S. National Science Foundation collects data on science and engineering (S&E) degrees awarded and publishes the results in Science and Engineering Degrees. During one year, 75.2% of S&E degrees awarded were for Bachelor s degrees and 37.8% of S&E degrees were Bachelor s degrees awarded to women. What percentage of S&E Bachelor s degrees were awarded to women? |
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| m102787 | The U.S. National Science Foundation publishes data on doctoral degrees conferred in the document Science and Engineering Doctorate Awards. The following joint probability distribution summarizes the doctoral degrees conferred in the social sciences and psychology by gender during one year.
a. Find P(G1), P(F1), and P(G1& F1).
b. Use the special multiplication rule to determine whether events G1 and F1 are independent. |
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| m102788 | The U.S. Senate consists of 100 senators, 2 from each state. A committee consisting of 5 senators is to be formed.
a. How many different committees are possible?
b. How many are possible if no state may have more than 1 senator on the committee?
c. If the committee is selected at random from all 100 senators, what is the probability that no state will have both of its senators on the committee? |
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| m102789 | The values listed below are the obtained values for a t statistic.
(1) What is your decision for each if df = 30 and α = .05 for a two-tailed test?
(2) What is your decision for each if df = 30, and we change to α = .01 for an upper-tail critical test?
(a) tobt = 2.050
(b) tobt = 1.680
(c) tobt = 2.834
(d) tobt = 3.030 |
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