Questions and Answers of Statistical Reasoning For Everyday Life

There were 1,038,280 bankruptcy cases filed last year, and in the year 2000 there were 1,276,900 bankruptcy cases filed Relative Change. Exercises each provide two values. For each pair of values,
The area codes (such as 617) of the telephone numbers of survey subjects.Qualitative versus Quantitative Data. In Exercises, determine whether the data described are qualitative or quantitative,and
In 2005, the average price of electricity was 10.0 cents per kWh (kilowatt-hour), and in 2015, the average price was 13.8 cents per kWh. Compare the increase in the price of electricity to the
If you spent $4.75 for a pound of coffee in 2015, what would the price have been in 2010?Coffee Index. In Exercises, use the following table of index numbers based on the price of a pound of coffee.
The U.S. population is now 323,447,281, and in 2000 it was 282,171,957.Relative Change. Exercises each provide two values. For each pair of values, use a percentage to express their relative change
Periodically, a survey is conducted in which subjects are asked if they wash their hands after using a public restroom.
The SAT scores of randomly selected applicants to colleges.Qualitative versus Quantitative Data. In Exercises, determine whether the data described are qualitative or quantitative,and explain why?
There are now 256 million registered passenger cars, and in 1990 there were 193 million.Relative Change. Exercises each provide two values. For each pair of values, use a percentage to express their
The number of households with a television in use when surveyed by Nielsen Media Research.Qualitative versus Quantitative Data. In Exercises, determine whether the data described are qualitative or
In 1980, the average price of a gallon of gas was $1.22, and in 2015 the average price was $2.52. Compare the increase in the price of a gallon of gasoline to the increase in price corresponding to
The average annual cost (tuition, fees, and room and board) at four-year public universities rose from $2550 in 1980 to $19,548 in 2015. Compare the increase in the cost of college to the increase in
The number of daily newspapers in the United States is now 1486, and it was 2226 in 1990.Relative Change. Exercises each provide two values. For each pair of values, use a percentage to express their
The television shows being watched by households surveyed by Nielsen Media Research.Qualitative versus Quantitative Data. In Exercises, determine whether the data described are qualitative or
The average annual cost (tuition, fees, and room and board) at four-year private colleges rose from $5600 in 1980 to $43,921 in 2015. Compare the increase in the cost of college to the increase in
In studying different prehistoric societies, an archeologist measures head circumferences of skulls.Qualitative versus Quantitative Data. In Exercises, determine whether the data described are
If you spent $14,222 for goods, services, and housing in 1985, what would the same purchases have cost in 2010?Consumer Price Index. In Exercises, use the Consumer Price Index values from Table 2.2.
Randomly selected adult subjects are asked to report their total annual income.
You spent $23,875 for goods, services, and housing in 2014, what would the same purchases have cost in 1980?Consumer Price Index. In Exercises, use the Consumer Price Index values from Table 2.2.
If you spent $12,250 on goods, services, and housing in 2000, what would the same purchases have cost in 2015?Consumer Price Index. In Exercises, use the Consumer Price Index values from Table 2.2.
The responses (yes, no, or no response) from survey subjects when asked a question.Qualitative versus Quantitative Data. In Exercises, determine whether the data described are qualitative or
Olympic athletes are categorized according to the sport in which they compete, such as track and field, cycling, or gymnastics.Qualitative versus Quantitative Data. In Exercises, determine whether
Measurements of blood alcohol concentration (BAC), which represent how much alcohol is found in the blood.Qualitative versus Quantitative Data. In Exercises, determine whether the data described are
If the CPI increases, must wage also increase? Explain.Does It Make Sense? For Exercises, determine whether the statement makes sense (or is clearly true) or does not make sense (or is clearly
Explain the difference between the terms percent (%) and percentage points. Give an example of how they can differ for the same situation.
Do a Web search using “benefit of tax cuts” and find an article arguing for or against a particular tax cut proposal or policy. Briefly summarize the article and discuss whether you think it made
Why can it be misleading to give measurements with more precision than is justified by the measurement process?Does It Make Sense? For Exercises, determine whether the statement makes sense (or is
A researcher measures the braking reaction time of a subject and records a value of 2.4 seconds, but the subject’s actual braking reaction time is 1.9 seconds. What is the relative error?
Minimum Wage. The following table lists the federal hourly minimum wage in both actual dollars at the time and 2012 dollars (based on data from the U.S. Department of Labor).a. According to the
Do you think that either of the charts in Figure 2.4 accurately portrays the overall “fairness” of the tax cuts? If so, which one and why? If not, how do you think the data could have been
Explain why temperatures on the Fahrenheit or Celsius scales are at the interval level of measurement while distances are at the ratio level.
In making price comparisons, why is it important to adjust prices for the effects of inflation? Briefly describe how we use the CPI to adjust prices.
Explain the difference between the key words of and more than when dealing with percentages. How are their meanings related?
The Academy Awards, the Heisman Trophy, and the New York Times “Bestseller List” are just three examples of selections that are determined by the votes of specially selected individuals. Pick one
Search through recent newspapers or journals and find an example of an observational, retrospective study. Briefly describe the study and summarize its conclusions
Motivated by a student’s death due to binge drinking, the College of Newport conducts a study of student drinking by randomly selecting 10 different classes and interviewing all of the students in
If all subjects in the aspirin treatment group are athletes and all subjects in the control group are not athletes, then there is a danger of which of the following: (a) Samples that are too
If we see a placebo effect, it means: (a) The experiment was not really double-blind(b) The experimental groups were too small(c) Pulse rates were lowered among some of those in the placebo
The purpose of the placebo is: (a) To prevent participants from knowing whether they belong to the treatment group or the control group; (b) To distinguish between the cases and the
The subjects do not know whether they are given aspirin or a placebo, and the evaluators who measure the pulse rates also do not know. This trial is: (a) Single-blind(b) Double-blind(c) Not
I wanted to know approximately what fraction of students at my school are left-handed, so I used a convenience sample in which I surveyed all of the students in my statistics class.
If we learn that the sample is representative of the population, which of the following best describes the results: (a) The results found for the sample are similar to those we would find for
In testing the effectiveness of a new vaccine, suppose that researchers used males for the treatment group and females for the placebo group. What is confounding, and how would it affect such an
z = -1.7 for H0 : μ = 36.9 degrees and Ha: μ 36.9 degreesUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score,
Researchers developed a questionnaire to identify compulsive buyers. A random sample of 32 subjects who identified themselves as compulsive buyers was obtained, and these subjects had a mean
When interpreting a P-value of 0.009, a researcher states that the results are statistically significant because the P value is very small, indicating that the results are not likely to occur by
A handy mnemonic for interpreting the P-value in a hypothesis test is this: “If the P (value) is low, then the null must go.Does It Make Sense? For Exercise, determine whether the statement makes
Test statistic: x2 = 3.957; significance level: 0.05 Test statistic: x2 = 3.499; significance level: 0.05 Survey Results. In the Exercise, assume that a yes/no survey question is presented to a
Investigate how GM crops may play a role in reducing global warming. Does this alter your own opinions about them in any way? Explain.
Test statistic: x2 = 12.336; significance level: 0.01Test statistic: x2 = 3.499; significance level: 0.05 Survey Results. In the Exercise, assume that a yes/no survey question is presented to a
A simple random sample of epicenter depths of 51 earthquakes has a mean of 9.808 kilometers (km) and a standard deviation of 5.013 km. Determine the critical value of t and the margin of error, and
Test statistic: x2 = 3.849; significance level: 0.01Test statistic: x2 = 3.499; significance level: 0.05 Survey Results. In the Exercise, assume that a yes/no survey question is presented to a simple
A random sample of adult females is partitioned into the age categories 18–24, 25–50, and over 50. The pulse rates of the subjects in the three different age categories are measured, and the
A random sample of M&Ms is partitioned into six categories according to color. The weights (in grams) are obtained, and the analysis of variance results are as shown in the display in Figure
Based on information from the National Cyber Security Alliance, 93% of computer owners believe that they have antivirus programs installed on their computers. In a random sample of 400 scanned
A study was conducted to estimate hospital costs for accident victims who wore seat belts. Twenty randomly selected cases have a distribution that appears to be approximately bell-shaped with a mean
A medical researcher wants to test the claim that healthy adults have a mean body temperature less than 98.6F.
In a KRC Research poll, 1002 adults were asked if they felt vulnerable to identity theft, and 53% of them said “yes.” Test the claim that the majority of adults feel vulnerable to identity
In a study of high school students at least 16 years of age, researchers obtained the survey results summarized in the accompanying table. Use a 0.05 significance level to test the claim of
Each car in a sample of seven cars was tested for nitrogen-oxide emissions (in grams per mile), and the following results were obtained: 0.06, 0.11, 0.16, 0.15, 0.14, 0.08, 0.15 (based on data from
A medical researcher wants to test the claim that healthy adults have a mean body temperature of 98.6F.
In a study of 1228 randomly selected medical malpractice lawsuits, it was found that 856 of them were dropped or dismissed. Test the claim that most medical malpractice lawsuits are dropped or
Workers and senior-level bosses were asked if it was seriously unethical to monitor emp oyee e-mails; the results are summarized in the following table (based on data from a Gallup poll). Use a 0.05
Listed below are lengths (in minutes) of randomly selected movies. The lengths of all movies are assumed to be normally distributed.110 96 125 94 132 120 136 154 149 94 119 132a. Construct a 95%
A student of one of the authors of this text lives in a home with a solar electric system. At the same time each day, she collected voltage readings (in volts) from a meter connected to the system
Listed below are measured amounts of greenhouse gas emissions from cars in three different categories. The measurements are in tons per year, expressed as CO2 equivalents. Use a 0.05 significance
In a USA Today article about an experimental vaccine for children, the following statement appeared: “In a trial involving 1602 children, only 14 (1%) of the 1070 who received the vaccine developed
The quality control manager at a manufacturing company claims that the proportion of defective transistors is greater than 0.03.
Listed below are brain volumes (in cubic centimeters or cm3) of adult subjects used in a study. Use the sample data to construct a 95% confidence interval estimate of the mean of the normally
The quality control manager at a manufacturing company claims that the proportion of defective transistors is 0.03.
Listed below are the measured “specific absorption rates” (SARs) of radiation (in watts per kilogram, or W/kg) from a sample of cell phones (when held to the head). The data are from the
A simple random sample of 16 different cereals is obtained, and the sugar content (in grams of sugar per gram of cereal) is measured for each cereal selected. Those amounts have a mean of 0.295 gram
Of the 98 participants in a drug trial who were given a new experimental treatment for arthritis, 56 showed improvement. Of the 92 participants given a placebo,49 showed improvement. Construct a
Find a journal article that refers to the use of analysis of variance. Identify the test being used and describe the conclusion. Did the test result in rejection of the existence of equal means? What
A sales representative claims that quarters inserted into her vending machines have a mean weight less than 5.64 grams.State the null and alternative hypothesis for a hypothesis, indicate whether the
z = -3.0 for H0: = 15 centimeters and Ha: μ = 15 centimetersUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and
z = -1.5 for H0: μ = 15 centimeters and Ha: μ <15 centimetersUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score,
The Genetics and IVF Institute conducted a clinical trial of the XSORT method designed to increase the probability of conceiving a girl. As of this writing, 945 babies were born to parents using the
A random sample of 760 subjects was obtained, and each was tested for left-handed writing. Among the 240 males, 23 wrote with their left hand. Among the 520 females, 65 wrote with their left hand.
The table below summarizes results from a survey of males aged 15 or older living in the Minhang District of China. The males are categorized by their educational attainment and whether they smoke.
z = 3.0 for H0: μ = 15 centimeters and Ha: μ 7 15 centimetresUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and
Find a recent news article discussing the salaries of players on different professional sports teams, such as several baseball teams. Find the salaries and use analysis of variance to test the null
A bookstore owner claims that the proportion of people who read books in print is not 0.23.State the null and alternative hypothesis for a hypothesis, indicate whether the hypothesis test will be
z = 1.5 for H0: μ = 15 centimeters and Ha: μ 7 15 centimetersUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and
A bookstore owner claims that the proportion of people who read books in print is greater than 0.25.State the null and alternative hypothesis for a hypothesis, indicate whether the hypothesis test
Given the claim that 10% of Americans are left-handed, randomly select at least 50 American students at your college and determine whether they are left-handed. Test the claim with a formal
Use the Internet or library references to determine the proportion of Americans who smoke. Test the claim that the proportion of American students at your college who smoke is different from the
z = 1.7 for H0: μ = 125 pounds and Ha: μ 125 poundsUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and determine
Use the Internet or library references to find the proportion of college students in the United States who are women. Test the claim that the proportion of women students at your college is different
z = 2.1 for H0: μ = 232 pounds and Ha: μ 232 poundsUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and determine
Choose two variables that appear to have a relationship that is worth investigating. One variable should have at least two categories of individuals—for example, two or more age categories, racial
z = -1.9 for H0: m = 0.55 liter and Ha: μ 0.55 literUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and
The Statistical Abstract of the United States and the Current Population Survey provide an extensive supply of social, economic, and vital statistics at the county, state, and local levels. Use their
It’s unusual to see a two-way table in a news article. But often a news story provides information that could be summarized in a two-way table. Find an article that discusses a relationship between
The Carolina Tobacco Company advertised that its best-selling nonfiltered cigarettes contain 40 milligrams of nicotine or less, but Consumer Advocate magazine ran tests on 10 randomly selected
News reports often describe the results of statistical studies in which the conclusions came from a hypothesis test involving two-way tables. However, the reports rarely give the actual table or
Use the sample data listed in Exercise 17 with a 0.05 significance level to test the claim that the sample is from a population with a mean equal to 1000 cm3 Exercise 17Listed below are brain
Think of an example of something you’d like to know that could be tested with a hypothesis test on a two-way table. Without actually collecting data or doing any calculations, describe how you
z = -2.7 for H0: m = 120.5 kilograms and Ha: μ120.5 kilogramsUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and
z = -2.1 for H0: m = 24.7 miles and Ha: μ 24.7 milesUsing P-Values to Reject or Not Reject. In Exercise, use Table A-1 to find the P-value that corresponds to the given standard score, and determine
Use the sample data listed in Exercise 18 with a 0.05 significance level to test the claim that the sample is from a population with a mean less than 1.6 W/kg.Exercise 18Listed below are the measured

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