Questions and Answers of Elementary Statistics

Shown below are pulse rates from Data Set 1 “Body Data” in Appendix B, and the XLSTAT display from two-way analysis of variance of these data. In analyzing these data, what important feature is
A study was conducted to determine whether amounts of tips left for servers are affected by giving guests free candy along with the bill. Four different groups were used: (1) No candy, (2) one
Obtain 18 straws from the cafeteria or supermarket. Cut 6 of them in half, cut 6 of them into quarters, and leave the other 6 as they are. There should now be 42 straws of different lengths. Put them
Working in groups of three or four, construct a brief survey that includes only a few questions that can be quickly asked. Include some objective questions along withsome that are biased, such as the
Data Set 33 “Disney World Wait Times” includes wait times (minutes) for the Tower o Terror ride at 5:00 PM. Use those times to test the claim that the median of all such wait times is equal
An example in this chapter referred to a survey of 410 human resource professionals. If those subjects are identified with numbers from 1 through 410, does it make sense to calculate the average
In class, each student should record two pulse rates by counting the number of heartbeats in 1 minute. The first pulse rate should be measured while the student is seated, and the second pulse rate
In Exercises 21–28, determine whether the study is an experiment or an observational study, and then identify a major problem with the study.When designing the study of a new treatment for insomnia
In Exercises 21–28, use the same list of cell phone radiation levels given for Exercises 17–20. Find the indicated percentile or quartile. P75
In Exercises 21–28, use the same list of cell phone radiation levels given for Exercises 17–20. Find the indicated percentile or quartile. P25
In the article “Weighing Anchors” in Omni magazine, author John Rubin observed that when people estimate a value, their estimate is often “anchored” to (or influenced by) a preceding number,
Identify any of the differences found from Exercise 1 that appear to be outliers. For any outliers, how much of an effect do they have on the mean, median, and standard deviation?Data from Exercise
Complete the following table, and then compare variation for each ride at 10 AM. See Data Set 33 “Disney World Wait Times''.Wait times (minutes) from six rides located in three different Walt
The standard deviation of the sample values in Exercise 1 is 43.1 km/h. What is the variance (including units)?Data from in exercise 1Listed below are maximum speeds (km>h) of randomly selected
Data Set 39 “Chocolate Chip Cookies” in Appendix B includes counts of chocolate chips in five different brands of cookies. Obtain your own sample of chocolate chip cookies and proceed to count
Appendix B includes many real and interesting data sets. In each group of three or four students, select a data set from Appendix B and analyze it using the methods discussed so far in this book.
In each group of three or four students, collect an original data set of values at the interval or ratio level of measurement. Provide the following:(1) A list of sample values(2) Software results of
In Exercises 5–12, determine whether the given procedure results in a binomial distribution or a distribution that can be treated as binomial (by applying the 5% guideline for cumbersome
In Exercises 5–12, determine whether the given procedure results in a binomial distribution or a distribution that can be treated as binomial (by applying the 5% guideline for cumbersome
In Exercises 5–12, determine whether the given procedure results in a binomial distribution or a distribution that can be treated as binomial (by applying the 5% guideline for cumbersome
Express the indicated degree of likelihood as a probability value between 0 and 1.Based on a study of the movies made in a recent year, 33 out of every 100 movies have a female lead or co-lead.
In Exercises 5–16, test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, or critical value(s), then state the conclusion about the null hypothesis, as
If we use the data given in Exercise 1, we get this 90% confidence interval estimate of the standard deviation of weights with the new minting process: 0.01686 g < σ < 0.03128 g. What does
Based on a Society for Human Resource Management survey, 36% of human resource professionals are at companies that rejected job candidates because of information found on their social media. If 25
In Exercises 5–12, determine whether the given procedure results in a binomial distribution or a distribution that can be treated as binomial (by applying the 5% guideline for cumbersome
a. Find the probability that when a single six-sided die is rolled, the outcome is 5.b. Find the probability that when a coin is tossed, the result is heads.c. Find the probability that when a
Use the sorted weights of M&Ms from the preceding exercise to find the value of P25. How does the result compare to the value of Q1?Data from in Preceding exerciseListed below are sorted weights
Listed below are self-reported heights of males aged 16 and over and their corresponding measured heights (based on data from the National Health and Nutrition Examination Survey). All heights are in
The boxplots shown below represent customer waiting times (minutes) for two different waiting lines. Which line would you prefer, or does it not make a difference? Explain.
The data listed below are estimated incomes (dollars) of students who graduated from the University of North Carolina (UNC) after majoring in geography. The data are based on graduates in the year
Listed below in order are prices in dollars for a Big Mac hamburger in the United States, Canada, Mexico, China, Japan, Russia, Switzerland, Italy, Spain, Britain, India, and Egypt. Such data are
In Exercises 17–20, use the following radiation levels (in W, kg) for 50 different cell phones. Find the percentile corresponding to the given radiation level. 0.48 W/kg 0.24 0.24 0.31 0.48 0.60
In Exercises 17–20, use the following radiation levels (in W, kg) for 50 different cell phones. Find the percentile corresponding to the given radiation level. 1.10 W/kg 0.24 0.24 0.31 0.48 0.60
In Exercises 17–20, use the following radiation levels (in W, kg) for 50 different cell phones. Find the percentile corresponding to the given radiation level. 0.98 W/kg 0.24 0.24 0.31 0.48 0.60
Match these values of r with the five scatterplots shown below: 0.268, 0.992, -1, 0.746, and 1.a.b.c.d.e. -1 y-2 -3- 4 0.0 0.1 0.2 0.3 0.4 X 0.5 0.6 0.7 0.8 0.9
Refer to Data Set 32 “Taxis” in Appendix B and use the distances (miles) and tip amounts (dollars) of all of the rides. Is there sufficient evidence to support the claim that there is a
Divide into groups of two or three students. The analysis of last digits of data can sometimes reveal whether values are the results of actual measurements or whether they are reported estimates.
Listed below are numbers of hospital admissions in one region due to traffic accidents on different Fridays falling on the 6th day of a month and the following 13th day of the month (based on data
Instead of using Table 7-2 for determining the sample size required to estimate a population standard deviation s, the following formula can also be usedWhere zα/2 corresponds to the confidence
Listed below are actual temperatures (°F) along with the temperatures that were forecast five days earlier (data collected by the author). Use a 0.05 significance level to test the claim that
In a randomized clinical trial of adults with an acute sore throat, 288 were treated with the drug dexamethasone and 102 of them experienced complete resolution; 277 were treated with a placebo and
When resampling data from two independent samples, what is the fundamental difference between bootstrapping and randomization?
Working in groups of three or four students, each group should make observations and collect data to determine whether there is a cost difference between genders for a particular product or service,
Before 1983, pennies were 97% copper and 3% zinc, but after 1983 they are 3% copper and 97% zinc. Using the data from Data Set 40 “Coin Weights” we get the statistics shown below. Use a 0.05
Construct the confidence interval that could be used to test the claim in Exercise 3. What feature of the confidence interval leads to the same conclusion from Exercise 3? Based on these results,
The test statistic of z = 2.14 is obtained when using the data from Exercise 1 and testing the claim that patients treated with dexamethasone and patients given a placebo have the same rate of
Pedometers are used to count the number of steps that a person walks. Those steps are often converted to distances, often by calibrating the pedometer. High school and college running tracks are
For the methods of this section, determine whether the following statements are true or false.a. When testing a claim with matched pairs of data, hypothesis tests using the P-value method, critical
When using the given sample results and the claim given in Exercise 1, the 95% confidence interval of 10.00732, 0.1592 is obtained. Data in Exercise 1In a randomized clinical trial of adults
Currently, keyboards have the keys configured in an arrangement referred to as “QWERTY” because of the placement of those particular letters on the second row from the top. Supposedly, that
Divide into groups according to gender, with about 10 or 12 students in each group. Each group member should record his or her pulse rate by counting the number of heartbeats in 1 minute, then the
Survey couples and record the number of credit cards each person has. Analyze the paired data to determine whether the males in couple relationships have more credit cards than the females. Try to
The author collected the data in the table below by randomly selecting cars in Connecticut and New York. Use a 0.05 significance level to test the claim that Connecticut and New York have the same
The sample size needed to estimate the difference between two population proportions to within a margin of error E with a confidence level of 1 - a can be found by using the following
Among 198 smokers who underwent a “sustained care” program, 51 were no longer smoking after six months. Among 199 smokers who underwent a “standard care” program, 30 were no longer smoking
Listed below are heights (in.) of mothers and their first daughters. The data are from a journal kept by Francis Galton. Use a 0.05 significance level to test the claim that there is no difference in
Listed below are heights (in.) of fathers and their first sons. The data are from a journal kept by Francis Galton. (See Data Set 10 “Family Heights” in Appendix B.) Use a 0.05 significance level
Construct a scatterplot and comment on the pattern of points. Cost of Dinner (dollars) Tip (dollars) 46.60 33.46 50.68 7.50 5.50 5.00 87.92 98.84 63.60 107.34 49.88 8.08 17.00 12.00 16.00 7.00
Randomly select a sample of male students and a sample of female students and ask each selected person a yes > no question, such as whether they support a death penalty for people convicted of
Construct a short survey of just a few questions, including a question asking the subject to report his or her height. After the subject has completed the survey, measure the subject’s height
The linear correlation coefficient r is found to be 0.846, the P-value is 0.008, and the critical values for a 0.05 significance level are {0.707. What should you conclude? Cost of Dinner
Using all of the Tour de France bicycle race results up to a recent year, we get this multiple regression equation: Speed = 29.2 - 0.00260 Distance + 0.540 Stages + 0.0570 Finishers, where Speed is
The author conducted an experiment in which the height of each student was measured in centimeters and those heights were matched with the same students’ scores on the first statistics test.a. For
If a restaurant were to change its tipping policy so that a constant tip of 20% of the bill is added to the cost of the dinner, what would be the linear regression equation relating the cost of the
If a restaurant were to change its tipping policy so that a constant tip of 20% of the bill is added to the cost of the dinner, what would be the value of the linear correlation coefficient for the
For each student in the class, measure shoe print length and height. Test for a linear correlation and identify the equation of the regression line. Measure the shoe print length of the professor and
Which of the following values change if the two variables of dinner cost and amount of tip are switched: the value of r = 0.846, the P-value of 0.008, the critical values of ± 0.707? Cost of Dinner
Use the same paired data from the preceding exercise.a. Find the linear regression equation.b. What is the best predicted amount of revenue for a casino with a size of 200 thousand square feet?
Each student should estimate the number of footsteps that he or she would walk between the door of the classroom and the door used to exit the building. After recording all of the estimates, each
a. What is a residual? b. In what sense is the regression line the straight line that “best” fits the points in a scatterplot?
Using the heights and weights described in Exercise 1, the linear correlation coefficient r is 0.394. Find the value of the coefficient of determination. What practical information does the
Divide into groups of 8 to 12 people. For each group member, use a string and ruler to measure head circumference and forearm length. Is there a relationship between these two variables? If so, what
Each student should use a sheet of paper and a paperclip to construct a “whirlybird” such as the one shown here. Instructions can be found on the Internet using the search term “make a
Here are the values of the world population (billions) beginning with the year 2000: 6.15 6.96 6.22 6.30 7.04 7.13 6.38 7.21 6.46 7.30 6.54 7.38 6.62 7.47 6.71 7.55 6.79 7.63 6.87 7.71
Use the value of the linear correlation coefficient r to find the coefficient of determination and the percentage of the total variation that can be explained by the linear relationship between the
Listed below are the numbers of deaths in the United States resulting from motor vehicle crashes. Use the best model to find the projected number of such deaths for the year 2025.
Divide into groups of 8 to 12 people. For each group member, measure height and arm span. For the arm span, the subject should stand with arms extended, like the wings on an airplane. Using the
Use the value of the linear correlation coefficient r to find the coefficient of determination and the percentage of the total variation that can be explained by the linear relationship between the
Leading digits of check amounts are often analyzed for the purpose of detecting fraud. The accompanying table lists frequencies of leading digits from checks written by the author (an honest
Use the value of the linear correlation coefficient r to find the coefficient of determination and the percentage of the total variation that can be explained by the linear relationship between the
Refer to Data Set 35 “Car Data” in Appendix B and use the weight, engine displacement, and highway fuel consumption (HWY) of all 48 cars. Find the best regression equation for predicting the
Use the value of the linear correlation coefficient r to find the coefficient of determination and the percentage of the total variation that can be explained by the linear relationship between the
Refer to Data Set 3 “ANSUR II 2012” in Appendix B and use the variables of Height, Foot_Length, and ArmSpan for all 6068 subjects. Find the best regression equation for predicting Height. Why is
Use the time>tip data from the table below, which includes data from New York City taxi rides (from Data Set 32 “Taxis” in Appendix B). (The distances are in miles, the times are in minutes,
Listed below are mean annual temperatures (°C) of the earth for each decade, beginning with the decade of the 1880s. Find the best model and then predict the value for 2090–2099. Comment on the
Listed below are the heights (cm) of winning presidential candidates and their main opponents from several recent presidential elections (from Data Set 22 “Presidents” in Appendix B). Find the
Use the distance/tip data from Exercise 15. Find the best predicted tip for a ride that is 3.10 miles. How does the result compare to the actual tip of $4.55?Data in Exercise 15.Use the time > tip
Use the time/fare data from Exercise 15 and find the best predicted fare amount for a time of 20 minutes. How does the result compare to the actual fare of $15.30?Data in Exercise 15Use the
Find the best predicted temperature at a time when a cricket chirps 3000 times in 1 minute. What is wrong with this predicted temperature? Chirps in 1 min Temperature (°F) 882 69.7 1188
In the table below, use the pizza cost and the subway fare. (Pizza cost is in dollars per slice, subway fare and CPI are in dollars.) What is the best predicted subway fare when pizza costs $4.00 per
Listed below are annual data for various years. The data are weights (pounds) of per capita consumption of mozzarella cheese and the numbers of civil engineering PhD degrees awarded (based on data
The following table lists results from an experiment designed to test the ability of dogs to use their extraordinary sense of smell to detect malaria in samples of children’s socks (based on data
Listed below are the annual numbers of cars sold (thousands) and the numbers of points scored in the Super Bowl that same year. What is the best predicted number of Super Bowl points in a year with
In Exercises based on the nature of the given data, do the following: In the following table, each column lists scores on a test of manual dexterity for brother/sister fraternal twins. The
Use the subway/CPI data from the preceding exercise. What is the best predicted value of the CPI when the subway fare is $3.00?
According to Benford’s law, for many data sets the leading digits of individual sample values follow the distribution shown in the first two rows of the following table. In normal and fair
Divide into groups of two or three students. Each group should conduct a survey by asking subjects to draw the letter X. Observe how the X is drawn and identify it as one of those shown below or
In 2006, use of the Hawk-Eye computer system was initiated at U.S. Open tennis matches. Players could challenge chair umpire and line judge calls, and the Hawk-Eye system was used to decide whether
The following table describes the distribution of eye colors reported by male and female statistics students (based on data from “Does Eye Color Depend on Gender? It Might Depend on Who or How You
The following table summarizes results from a Pew Research Center survey in which subjects were asked whether they had seen or been in the presence of a ghost. Use a 0.01 significance level to test

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