Questions and Answers of Statistics Informed Decisions Using Data

A family doctor is interested in examining the relationship between a patient's age and total cholesterol (in \(\mathrm{mg} / \mathrm{dL}\) ). He randomly selects 14 of his female patients and
Compute the standard error of the estimate for the data in Table 1.Approach Use the following steps to compute the standard error of the estimate.Step 1 Find the least-squares regression line.Step 2
Test whether a linear relation exists between age and total cholesterol at the \(\alpha=0.05\) level of significance using the data in Table 1 from Example 1.Approach Verify that the requirements to
Determine a 95% confidence interval for the slope of the true regression line for the data presented in Table 1 in Example 1.By-Hand ApproachStep 1 Determine the least-squares regression line.Step 2
Use the data in Table 4.(a) Find the least-squares regression equation \(\hat{y}=b_{0}+b_{1} x_{1}+b_{2} x_{2}\), where \(x_{1}\) represents the patient's age, \(x_{2}\) represents the patient's
For the model obtained in Example 2, determine the coefficient of determination and the adjusted \(R^{2}\). Compare the \(R^{2}\) with the two explanatory variables age and daily saturated fat to the
Construct a 95% confidence interval for a mean response and a 95% prediction interval for an individual response for a 32-year-old female who consumes 23 grams of saturated fat daily using the model
Using the data presented in Table 5:(a) Find the correlation matrix among all three variables.(b) Find the least-squares regression model using both \(x_{1}\) and \(x_{2}\) as explanatory
The wind chill index represents what the air feels like on exposed skin while factoring in wind speed. The wind chill index is determined by considering the wind speed at a height of 5 feet, the
The data in Table 7 represent the number of licensed drivers in various age groups and the number of fatal accidents within the age group by gender.(a) Draw a scatter diagram of the data treating
Researchers developed a model to predict the age, \(y\), of an individual based on the gender of the individual, \(x_{1}(0=\) female, \(1=\) male \()\), the height of the second premolar, \(x_{2}\),
Photosynthetic efficiency is the percentage of light energy that is converted into chemical energy by a plant. The chemical energy is used by a plant to maintain the plant's activities. A sample of
The data in Table 9 represent the miles per gallon (MPG) along with potential explanatory variables weight (in thousands of pounds), number of cylinders, and horsepower. Use a partial \(F\)-test to
An engineer wants to develop a model to describe the gas mileage of a sport utility vehicle. He collects the data presented in Table 10. The final drive ratio is the ratio of the gear set that is
Use the backward elimination procedure to find the best model to describe miles per gallon for the data in Table 10. Use a level of significance of \(\alpha=0.05\) as the criteria for an explanatory
Crickets make a chirping noise by sliding their wings rapidly over each other. Perhaps you have noticed that the number of chirps seems to increase with the temperature. The following table lists the
We record the gender of the 15 students enrolled in an introductory statistics course as they enter the classroom. The males are denoted by a blue M and the females are denoted by a red
Prosthodontists specialize in the restoration of oral function, including the use of dental implants, veneers, dentures, and crowns. Since repairing chipped veneer is less costly and time-consuming
The researcher in Example 1 wants to determine if there is a difference in the mean shear bond strength among the four treatment groups at the \(\alpha=0.05\) level of significance.Approach We will
In Example 3 from Section 13.1, we rejected the null hypothesis \(H_{0}: \mu_{\text {Cojet }}=\mu_{\text {Silistor }}=\mu_{\text {Cimara }}=\mu_{\text {Ceramic }}\). Use Tukey's test to determine
Zocor is a drug manufactured by Merck and Co. that is meant to reduce the level of LDL (bad) cholesterol and increase the level of HDL (good) cholesterol. In clinical trials of the drug, patients
Invest in Education Go to the book's website to obtain the data file 14_1_17. The variable "2013 Cost" represents the fouryear cost including tuition, supplies, room and board, the variable "Annual
Interpret the regression coefficients for the least-squares regression equation found in Example 2.Approach Interpret the coefficients the same way as we did for a regression with one explanatory
What was the mean price of the security on the first of January 2004?
How would you describe the price movement of the security during the third quarter (01-July-2004 to 01-Oct-2004)?
What is the change in value for this security over the four quarters recorded in the high–low–close graph?
Which of the three quarters exhibited the most consistent increase in value for this security?
For the year 1995, what are the maximum sales for women’s clothing and the minimum for men’s?
What are the medians for the range (maximum to minimum) for the years 1989 and 1998? Was there an identifiable trend over the 10 years between these two values?
What happened to the average sales figures for jewelry over the 10-year period?
Which of the 10 years had the most and least variability between the maximum sales of women’s clothing and the minimum for men’s, and what were those ranges?
Which of the two groups, those that defaulted or did not, had the most variability for the maximum in other debt and the minimum for their credit card debt?
What are the ranges (maximum other debt and the minimum credit card debt) for those defaulting and those that have not, and which is the smallest?
Can you identify a pattern between the two groups representing those that have defaulted and those that have not for the debt-to-income and the size of their ranges?
Which groups have the largest and smallest mean debt-to-income ratio?
What are the mean differences for all educational groupings on default history?
In which of the five educational categories does the default history have the least impact on the debt-to-income ratio?
Which of the 10 groups has the most and the least variability in the maximum other debt and minimum credit card debt?
(a) In which month was the highest sale of women’s clothing recorded and what was that amount?(b) What direction did the mean of the range bar move between months 11 and 12?(c) What direction did
(a) What is the age of the oldest male who has a college degree?(b) What is the fewest number of years of education for the females?(c) Which category for both males and females has the most years of
(a) What is the age of the oldest person who has earned a college degree?(b) What is the fewest number of years of education attained by any of the respondents?(c) Which category has the most years
(a) What is the lowest price of the stock, and approximately when did this occur?(b) What is the highest price of the stock, and approximately when did this occur?(c) Which month for purchasing the
(a) Is there a significant difference in the ages for the married and unmarried groups?(b) What is the minimum income for unmarried individuals before the work program?(c) What is the maximum income
(a) What percentage of White respondents have no children?(b) What percentage of Black respondents have five children?(c) What percentage of respondents who belong to the Other Category have four
(a) What percentage of those who live in the North East have an exciting life?(b) What percentage of those who live in the South East have a Routine life? (c)What percentage of those who live in the
(a) What is the most years of education obtained by minorities and nonminorities?(b) What is the trend in earnings for the nonminority after 15 years of education?(c) What is the highest salary
(a) What is the oldest age interval for those who did not complete high school, and how many are in that interval?(b) Which age interval and level of education classification contains the largest
(a) What percentage of the total respondents are White and have no children?(b) What percentage are Black and have no children?(c) What percentage belongs to the Other category and have no
What job category, for males, has the highest percentage of employees?
What job category, for females, has the highest percentage of employees?
In general, what might be said about the percentages for all job categories when comparing males and females?
What are the job category ranks, from the highest to the lowest, for females and males, and are they the same?
Which region of the United States has the highest percentage of the Black race category?
Which region of the United States has the lowest percentage of Blacks?
What is the rank order (from the highest to the lowest) of the region choices for the Black race?
Which of the three job classifications has the greatest difference in mean salaries for minority and nonminority classification?
Which of the three job categories has the smallest salary difference for minorities and nonminorities?
Which of the three job categories has the second smallest salary difference for minorities and nonminorities?
How many married individuals are aged 19.5 to 20.5 years?
Which of the groups (married or unmarried) has the most individuals aged 20.5 to 21.5 years, and how many individuals of this age does each group contain?
Which of the age groups (married or unmarried) has the lowest number of individuals aged 15.5 to 16.5 years and how many individuals of this age does each group contain?
What is the age interval that contains the most unmarried individuals, and how many individuals does this interval contain?
What is the age interval that contains the most married individuals and how many individuals does this interval contain?
What percentage of female managers is classified as minorities?
In which of the six subgroups (panels) are the differences between minority and nonminority the least, and what are the percentages?
Which of the subgroups shows the greatest percentage difference between minority and nonminority employees?
What percentage of male managers is classified as nonminority?
What percentage of female respondents is employed as custodians?
Which panel reported the largest percentage of nonminority females employees?
Which of the subgroups reports a distribution of minority and nonminority that approximates equality, and what are the percentages?
What percentage of the total respondent population is classified as nonminority female managers?
Which subgroup reports the largest percentage of minority employees?
What percentage of the male managers is classified as minority?
What is the mean current salary for minority females who do clerical work?
What is the mean current salary for males who do clerical work and are not part of a minority group?
Which of the subgroups (panels) shows the greatest difference in salof the subgroups (panels) shows the greatest difference in salary between minority and nonminority employees, and what are the
Is there any difference in the mean current salary for minority and nonminority females working as custodians?
Which of the nine subgroups has the highest salary, and what is the amount?
Do nonminority male and female managers have the same mean salary, and what are the amounts?
Describe which two employment categories of males have the least difference in salary between minority and nonminority?
How many married males aged 15.5 to 16.5 years were enrolled in the work program?
Which age category has the most married females, and how many are there in that category?
Is there an identifiable age pattern for unmarried and married females? If you can identify a pattern, describe it in terms of similarities between the two groups.
Which of the four groups has the fewest numbers enrolled in the work program?
(a) What percentage of males who voted in the last election live in the Northern region?(b) What percentage of females who voted in the last election live in the Northern region?(c) Which region has
(a) What percentage of the total respondents live in the Eastern region, are females, and did not vote in last election?(b) What percentage of the total respondents live in the Central region, are
(a) What is the mean age for those respondents who said that they are White, live in the North East, and are very happy?(b) What is the mean of those who said that they belong to the Other category,
(a) Just by looking at the graph, identify which of the row panels (Level of education) contains the most people?(b) Which of the six groups has the most participants in the age interval 17.5 to 18.5
(a) What percentage of the males who had contact with the employee visited the store for price reasons?(b) What percentage of females who had contact with the employee visited the store for price
(a) In one word, how would you describe the relationship between web hits and sales of CDs? For the y-axis, change to read Maximum of 1,600 and Major Increment of 250. The x-axis should have a Major
(a) What does the large black mass found at the bottom left-hand side of the graph indicate?(b) What are the strength and direction of the relationship between the two variables?(c) What was the
(a) On average, how many years would a 36-year-old person have been employed?(b) What are the strength and direction of the relationship?(c) What is the range of years with the employer for someone
(a) On the average, spending 32,000 on print advertising would result in what amount of jewelry sales?(b) What are the strength and direction of the relationship?(c) What is the average cost of print
(a) On average, if sales of men’s clothing reach 30,000 what would be the expected sales for women’s clothing?(b) What are the strength and direction of the relationship?(c) What is the expected
What type of vehicle has the most horsepower and largest engine, and what is its horsepower and engine size?
Using the correct best fit line, what is the estimated engine size for an automobile having 400 horsepower? What size would a truck engine be if it had the same horsepower rating?
What are the correlation coefficients for engine size and horsepower for automobiles and trucks in this study?
For these 157 vehicles, what is the horsepower and largest engine size for the truck category?
What could you say about the strength, direction, and shape of the relationship between engine size, horsepower, and type of vehicle from the information conveyed by the scatterplot?
(a) Which of the vehicle types has a correlation coefficient closest to zero?(b) For the truck category, does the graph tell you that size of the truck, as measured by the wheelbase, have any

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