Questions and Answers of Essentials Of Statistics

What characteristic of a data set can be better understood by constructing a histogram?
Which of the following graphs would be best for visually illustrating the data in the table: histogram; dotplot; scatterplot; Pareto chart; stemplot?Refer to the table in the margin, which summarizes
Is the level of measurement of the 641 individual responses nominal, ordinal, interval, or ratio? Why?Refer to the table in the margin, which summarizes results from 641 people who responded to a USA
Misleading Graph How is the accompanying graph misleading? How could it be modified so that it would not be misleading?Refer to the table in the margin, which summarizes results from 641 people who
In conducting a statistical study, why is it important to consider the source of the data?
Correlation and Causation What is meant by the statement that “correlation does not imply causation”?
In a survey of 109 subjects, each was asked to indicate how many text messages they send and receive each day. The sample consisted of those who chose to respond to the request posted on the
In a survey of 514 human resource professionals, each was asked about the importance of the appearance of a job applicant. The survey subjects were randomly selected by Harris Interactive
In a survey of beliefs about evolution, Gallup pollsters randomly selected and telephoned 1018 adults in the United States.Determine whether the sampling method appears to be sound or is flawed.
In a study of the Marisa Waite diet, four subjects lost an average of 45 pounds. It is found that there is about a 30% chance of getting such results with a diet that has no effect.Determine whether
The listed pulse rates were obtained for the Third National Health and Nutrition Examination Survey conducted by the U.S. Department of Health and Human Services, National Center for Health
The data in the table were obtained by members of departments at Harvard Medical School, Massachusetts General Hospital, Dartmouth College, Dartmouth Medical School, and the University of California
If we were to use such data and conclude that there is a correlation or association between IQ score and brain volume, does it follow that larger brains are the cause of higher IQ scores? IQ Score
Parameter and Statistic What is a parameter, and what is a statistic?
Identifying the Population In a Gallup poll of 1010 adults in the United States, 55% of the respondents said that they used local TV stations daily as a source of news. Is the 1010 value a statistic
Distracted Driving In a AAA Foundation for Traffic Safety survey, 21% of the respondents said that they recently texted or e-mailed while driving.Determine whether the given value is a statistic or a
States There are 50 state capitols in the United States.Determine whether the given value is a statistic or a parameter.
Late Flights Among the flights included in the sample of flights in Data Set 15 of Appendix B, 21% arrived late.Determine whether the given value is a statistic or a parameter. Data set name is
IQ Scores The mean IQ score for subjects taking the Wechsler Adult Intelligence Scale IQ test is 100.Determine whether the given value is a statistic or a parameter.
Brain Volume The average (mean) volume of the brains included in Data Set 6 of Appendix B is 1126.0 cm3.Determine whether the given value is a statistic or a parameter. Data Set 6: IQ and Brain Size
HDTV Penetration In a random sample of households, it was found that 47% of the sampled households had high-definition TVs.Determine whether the given value is a statistic or a parameter.
Honda Civic Crash Test In Data Set 13 of Appendix B, the measured chest deceleration of a Honda Civic in a crash test is 39 g, where g is a force of gravity.Determine whether the given values are
Honda Civic Cylinders The Honda Civic has 4 cylinders.Determine whether the given values are from a discrete or continuous data set.
Word Count From Data Set 17 in Appendix B we see that a male spoke 13,825 words in one day.Determine whether the given values are from a discrete or continuous data set. Data Set 17: Word Counts by
First President George Washington was 188 cm tall.Determine whether the given values are from a discrete or continuous data set.
House of Representatives Currently the House of Representatives has 435 members.Determine whether the given values are from a discrete or continuous data set.
Crash Test Results Data Set 13 in Appendix B includes crash test results from 21 different cars.Determine whether the given values are from a discrete or continuous data set. Data Set 13: Car Crash
Earthquake From Data Set 16 in Appendix B we see that an earthquake had a measurement of 0.70 on the Richter scale.Determine whether the given values are from a discrete or continuous data set. Data
Arm Circumference From Data Set 1 in Appendix B we see that a female had an arm circumference of 27.5 cm.Determine whether the given values are from a discrete or continuous data set. Data Set 1:
Years in which U.S. presidents were inaugurated. Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate.
The movie Avatar was given a rating of 4 stars on a scale of 5 stars.Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate.
Volumes (cm3) of brains listed in Data Set 6 of Appendix B. Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Data Set 6: IQ and Brain Size
Car models (Chevrolet Aveo, Honda Civic, . . . , Buick Lucerne) used for crash testing, as listed in Data Set 13 of Appendix B. Determine which of the four levels of measurement (nominal, ordinal,
Political Parties In a preelection survey of likely voters, political parties of respondents are identified as 1 for a Democrat, 2 for a Republican, 3 for an Independent, and 4 for anything else. The
Flight Numbers Data Set 15 in Appendix B lists flight numbers of 48 different flights, and the average (mean) of those flight numbers is 11.0.Identify the level of measurement of the data. Also,
World Series Champs As of this writing, the New York Yankees were the last team to win the World Series, and the numbers of the starting lineup are 2, 18, 25, 13, 20, 55, 24, 33, and 53. The average
The Milgram Research Company wants to study reactions to stress, so it administers surveys in which the person asking the questions pretends to become very angry with the survey subject. At one
In a clinical trial of the cholesterol drug Lipitor, 188 subjects were given 20-mg doses of the drug, and 3.7% of them experienced nausea (based on data from Pfizer, Inc.).Determine whether the given
In a study sponsored by Coca-Cola, 12,500 people were asked what contributes most to their happiness, and 77% of the respondents said that it was their family or partner.Determine whether the given
The author collected sample data by randomly selecting 12 different pages from Harry Potter and the Sorcerer’s Stone and then finding the number of words in each sentence on each of those
In a Pew Research Center poll, 1007 adults were called after their telephone numbers were randomly generated by a computer, and 85% of the respondents were able to correctly identify what Twitter
When collecting data from different sample locations in a lake, a researcher uses the “line transect method” by stretching a rope across the lake and collecting samples at every interval of 5
The CBS News station in New York City often obtains opinions by interviewing neighbors of a person who is the focus of a news story.Identify which of these types of sampling is used: random,
The author collected sample data by randomly selecting 20 different pages from a printed version of the Merriam-Webster Dictionary and then counting the number of defined words on each of those
The New York State Department of Transportation evaluated the quality of the New York State Throughway by testing core samples collected at regular intervals of one mile.Identify which of these types
In order to test for a gender gap in the way that men and women purchase cars, the Grant Survey Company polls exactly 750 adult men and 750 adult women randomly selected from adults in the United
According to the State of New York Unified Court System, names of potential jurors are selected from a variety of different sources. When a trial requires a jury, names from the list are randomly
The Nurses’ Health Study was started in 1976 with 121,700 female registered nurses who were between the ages of 30 and 55. The subjects were surveyed in 1976 and every two years thereafter. The
In order to study the seriousness of drinking and driving, a researcher obtains records from past car crashes. Drivers are partitioned into a group that had no alcohol consumption and another group
Researchers from the National Institutes of Health want to determine the current rates of smoking among adult males and adult females. They conduct a survey of 500 adults of each gender.Indicate
Researchers at the National Cancer Institute studied meat consumption and its relationship to mortality. Approximately one-half million people were surveyed, and they were then followed for a period
Lisinipril is a drug designed to lower blood pressure. In a clinical trial of Lisinipril, blood pressure levels of subjects are measured before and after they have been treated with the drug.Identify
A clinical trial of aspirin treatments is being planned to determine whether the rate of myocardial infarctions (heart attacks) is different for men and women.Identify which of these designs is most
The numbers of the current players for the Chicago Bulls basketball team are 1, 2, 3, 5, 6, 9, 11, 13, 16, 20, 22, 26, 32, and 40. Does it make sense to calculate the average (mean) of these numbers?
Which of the following best describes the level of measurement of the data listed in Exercise 1: nominal, ordinal, interval, ratio?Exercise 1Literary Digest magazine conducted a poll for the 1936
Data Set 16 includes depths (km) of the sources of earthquakes. Are these values discrete or continuous? Data Set 16: Earthquake Measurements Fifty matched pairs of magnitude/depth measurements
Are the earthquake depths described in Exercise 3 quantitative data or categorical data?Exercise 3In a test of the Atkins weight loss program, 40 subjects using that program had a mean weight loss of
Which of the following best describes the level of measurement of the earthquake depths described in Exercise 3: nominal, ordinal, interval, ratio?Exercise 3In a test of the Atkins weight loss
True or false: If you construct a sample by selecting every sixth earthquake depth from the list given in Data Set 16, the result is a simple random sample. Data Set 16: Earthquake Measurements Fifty
In a recent Gallup poll, pollsters randomly selected adults and asked them whether they smoke. Because the subjects agreed to respond, is the sample a voluntary response sample?
In a recent Gallup poll, pollsters randomly selected adults and asked them whether they smoke. Among the adults who responded to the survey question, 21% said that they did smoke. Is that value of
True or false: If data lead to a conclusion with statistical significance, then the results also have practical significance.
Find the probability of selecting someone who does not use drugs. Does the result appear to be reasonable as an estimate of the proportion of the adult population that does not use drugs?In refer to
Based on Data Set 1 “Body Data” in Appendix B, blood platelet counts of women have a bell-shaped distribution with a mean of 255.1 and a standard deviation of 65.4. (All units are 1000 cells /
An Ohio college student died when he tried to escape from a dormitory elevator that was overloaded with 24 passengers. The elevator was rated for a maximum weight of 2500 pounds. Let’s
a. Grades (A, B, C, D, F) earned in statistics classesb. Heights of students in statistics classesc. Numbers of students in statistics classesd. Eye colors of statistics studentse. Numbers of times
There are about 11,000 births each day in the United States, and the proportion of boys born in the United States is 0.512. Assume that each day, 100 births are randomly selected and the proportion
USA Today provided results from a poll of 1000 adults who were asked to identify their favorite pie. Among the 1000 respondents, 14% chose chocolate pie, and the margin of error was given as {4
A bone mineral density test is used to identify a bone disease. The result of a bone density test is commonly measured as a z score, and the population of z scores is normally distributed with a mean
Greater than 3.00 minutesIn refer to the continuous uniform distribution depicted in Figure 6-2 and described in Example 1. Assume that a passenger is randomly selected, and find the probability that
Data Set 4 “Births” in Appendix B includes birth weights of 400 babies. If we compute the values of sample statistics from that sample, which of the following statistics are unbiased estimators
Standing eye heights of men are normally distributed with a mean of 64.3 in. and a standard deviation of 2.6 in. (based on anthropometric survey data from Gordon, Churchill, et al.).a. If an eye
Data Set 4 “Births” in Appendix B includes birth weights of 400 babies. If we compute the values of sample statistics from that sample, which of the following statistics are unbiased estimators
A geneticist is investigating the proportion of boys born in the world population. Because she is based in China, she obtains sample data from that country. Is the resulting sample proportion a good
In find the critical value Zα/2 that corresponds to the given confidence level.90%
a. If 1 adult female is randomly selected, find the probability that her pulse rate is less than 80 beats per minute.b. If 16 adult females are randomly selected, find the probability that they have
Less than 4.00 minutesIn refer to the continuous uniform distribution depicted in Figure 6-2 and described in Example 1. Assume that a passenger is randomly selected, and find the probability that
In assume that scores on a bone mineral density test are normally distributed with a mean of 0 and a standard deviation of 1.a. Identify the values of μ and σ for the standard normal
a. If 1 adult female is randomly selected, find the probability that her pulse rate is greater than 70 beats per minute.b. If 25 adult females are randomly selected, find the probability that they
In find the critical value Zα/2 that corresponds to the given confidence level.99.5%
Between 2 minutes and 3 minutesIn refer to the continuous uniform distribution depicted in Figure 6-2 and described in Example 1. Assume that a passenger is randomly selected, and find the
Between 2.5 minutes and 4.5 minutesIn refer to the continuous uniform distribution depicted in Figure 6-2 and described in Example 1. Assume that a passenger is randomly selected, and find the
With n = 20 guesses and p = 0.2 for a correct answer, find P(at least 6 correct answers).In do the following: If the requirements of np ≥ 5 and nq ≥ 5 are both satisfied, estimate the indicated
In assume that females have pulse rates that are normally distributed with a mean of 74.0 beats per minute and a standard deviation of 12.5 beats per minute (based on Data Set 1 “Body Data” in
a. If 1 adult female is randomly selected, find the probability that her pulse rate is between 78 beats per minute and 90 beats per minute.b. If 16 adult females are randomly selected, find the
Express 0.0434 < p < 0.217 in the form of p̂ + E.In express the confidence interval using the indicated format. (The confidence intervals are based on the proportions of red, orange, yellow,
Example 2 referred to an elevator with a maximum capacity of 4000 lb. When rating elevators, it is common to use a 25% safety factor, so the elevator should actually be able to carry a load
The accompanying normal quantile plot was constructed from the diastolic blood pressure levels of a sample of women. What does this graph suggest about diastolic blood pressure levels of women?In
Express 0.179 < p < 0.321 in the form of p̂ + E.In express the confidence interval using the indicated format. (The confidence intervals are based on the proportions of red, orange, yellow,
Find the probability that a male has a back-to-knee length less than 21 in.Inuse the data in the table below for sitting adult males and females (based on anthropometric survey data from Gordon,
Express the confidence interval (0.0169, 0.143) in the form of p̂ – E < p < p̂ + E.In express the confidence interval using the indicated format. (The confidence intervals are based on the
Repeat Exercise 11 using medians instead of means.Data From Exercise 11a. After identifying the 16 different possible samples, find the mean of each sample, then construct a table representing the
Express the confidence interval 0.270 ± 0.073 in the form of p̂ – E < p < p̂ + E.In express the confidence interval using the indicated format. (The confidence intervals are based on the
Find the probability that a female has a back-to-knee length greater than 24.0 in.Inuse the data in the table below for sitting adult males and females (based on anthropometric survey data from
Exercise 9 “Cookies”Data From Exercise 9The numbers of chocolate chips in Chips Ahoy (reduced fat) cookies, as listed inData Set 28 “Chocolate Chip Cookies” in Appendix B.In use the Excel, or
Repeat Exercise 11 using variances instead of means.Data from in Exercise 11a. After identifying the 16 different possible samples, find the mean of each sample, then construct a table representing
Exercise 10 “Ages of Best Actresses”Data From Exercise 10The ages of actresses at the times that they won Oscars, as listed in Data Set 14 “Oscar Winner Age” in Appendix B.In use the Excel,
For males, find P90, which is the length separating the bottom 90% from the top 10%.Inuse the data in the table below for sitting adult males and females (based on anthropometric survey data from
Exercise 11 “Garbage”Data From Exercise 11The weights (pounds) of discarded yard waste, as listed in Data Set 31 “Garbage Weight” in Appendix B.In use the Excel, or StatCrunch) or a
Based on a study by Dr. P. Sorita at Indiana University, assume that 12% of us have green eyes. In a study of 650 people, it is found that 86 of them have green eyes.a. Find the probability of at

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