Questions and Answers of Elementary Statistics 7th

An automobile manufacturer claims that the variance of the fuel consumptions for its hybrid vehicles is less than the variance of the fuel consumptions for the hybrid vehicles of a top competitor. A
Compare your results in Exercise 43 with the equation of the regression line and its graph in Exercise 41. Which equation is a better model for the data? Explain.Use the data shown in the table given
Compare your results in Exercise 39 with the equation of the regression line and its graph in Exercise 37. Which equation is a better model for the data? Explain.Use the data shown in the table given
Find the equation of the regression line for the data. Then construct a scatter plot of (x, y) and sketch the regression line with it.Use the data shown in the table given below, which shows the
An instructor for a SAT preparation course claims that the course will improve the test scores of students. The table shows the critical reading scores for 10 students the first two times they took
Claim: µ1 < µ2; α = 0.05Population statistics: σ1 = 75 and σ2 = 105Sample statistics: x̅1 = 2435, n1 = 35 and x2 = 2432, n2 = 90Test the claim about the difference between two population
What conditions are necessary in order to use the z@test to test the difference between two population means?
Explain how to perform a two-sample z-test for the difference between two population means using independent samples with σ1 and σ2 known.
Explain how to perform a two-sample t@test for the difference between two population means.
What conditions are necessary in order to use the t@test to test the difference between two population means?
A researcher claims that the percentage of adults in the United States who own a video game system is not 26%.Describe type I and type II errors for a hypothesis test of the indicated claim.
Test the claim about the population mean m at the level of significance a. Assume the population is normally distributed.Claim: M = 7450; α = 0.10; σ = 243. Sample statistics: x̅ = 7495, n = 27
An education publication claims that the mean in-state tuition and fees at public four-year institutions by state is more than $9000 per year. A random sample of 30 states has a mean in-state tuition
State whether each standardized test statistic t allows you to reject the null hypothesis. Explain.(a) t = -1.755(b) t = -1.585(c) t = 1.745 -2|-i i /2 'o = 1.725 -4 -3 -2 -1 1 3 4 -1o =-1.725
Test the claim about the population mean µ at the level of significance a. Assume the population is normally distributed.Claim: µ > 12,700; α = 0.005.Sample statistics: x̅ = 12,855, σ = 248,
Determine the finite population correction factor for each value of N and n.(a) N = 1000 and n = 500 (b) N = 1000 and n = 100(c) N = 1000 and n = 75 (d) N = 1000 and n = 50(e) N = 100 and n
A group of researchers estimates the mean length of time (in minutes) the average U.S. adult spends watching television using digital video recorders (DVRs) and other forms of time-shifted television
When all other quantities remain the same, how does the indicated change affect the width of a confidence interval? Explain.(a) Increase in the level of confidence(b) Increase in the sample size(c)
Gold Prices From a random sample of 48 business days from January 4, 2010, through February 24, 2017, U.S. gold prices had a mean of $1368.48. Assume the population standard deviation is $202.60.You
Construct the indicated confidence interval for the population mean µ.c = 0.80, x̅ = 20.6, σ = 4.7, n = 100
Construct the indicated confidence interval for the population mean µ.c = 0.99, x̅ = 10.50, σ = 2.14, n = 45
Construct the indicated confidence interval for the population mean µ.c = 0.95, x̅ = 31.39, σ = 0.80, n = 82
Construct the indicated confidence interval for the population mean µ.c = 0.90, x̅ = 12.3, σ = 1.5, n = 50
The grade point averages of 14 randomly selected college students2.3 3.3 2.6 1.8 3.1 4.0 0.7 2.3
Find the critical values x2R and x2L for the level of confidence c and sample size n.c = 0.99, n = 15
What happens to the shape of the chi-square distribution as the degrees of freedom increase?
The histogram shows the distribution of hurricanes that have hit the U.S. mainland from 1851 through 2015 by Saffir-Simpson category, where 1 is the weakest level and 5 is the strongest level.(a)
Determine the missing probability for the probability distribution. 3 4 5 6 P(x) 0.05 ? 0.23 0.21 0.17 0.11 0.08 2. 1.
Determine the missing probability for the probability distribution. 3 4 P(x) 0.06 0.12 0.18 ? 0.30 1.
Use the probability distribution you made in Exercise 20 to find the probability of randomly selecting an employee whose overtime is(a) One or two hours,(b) Two hours or less,(c) Between three and
Use the probability distribution you made in Exercise 19 to find the probability of randomly selecting a household that has(a) One or two HD televisions,(b) Two or more HD televisions,(c) Between one
The number of high-definition (HD) televisions per household in a small town(a) Construct a probability distribution,(b) Graph the probability distribution using a histogram and describe its shape.
The histogram represents a binomial distribution with 5 trials. Match the histogram with the appropriate probability of success p. Explain your reasoning.(a) p = 0.25(b) p = 0.50(c) p = 0.75 P(x)
The histogram represents a binomial distribution with 5 trials. Match the histogram with the appropriate probability of success p. Explain your reasoning.(a) p = 0.25(b) p = 0.50(c) p = 0.75 P(x)
The histogram represents a binomial distribution with 5 trials. Match the histogram with the appropriate probability of success p. Explain your reasoning.(a) p = 0.25(b) p = 0.50(c) p = 0.75 P(x)
The histogram represents a binomial distribution with 5 trials. Match the histogram with the appropriate probability of success p. Explain your reasoning.(a) p = 0.25(b) p = 0.50(c) p = 0.75 P(x)
P(A) = 0.62, P(A') = 0.38, P(B|A) = 0.41, and P(B|A') = 0.17Use Bayes’ Theorem to find P(A|B).According to Bayes’ Theorem, the probability of event A, given that event B has occurred, is Р(A) :
P(A) = 0.25, P(A') = 0.75, P(B|A) = 0.3, and P(B|A') = 0.5Use Bayes’ Theorem to find P(A|B).According to Bayes’ Theorem, the probability of event A, given that event B has occurred, is Р(A) :
P(A) = 3/8, P(A') = 5/8, P(B|A) = 2/3, and P(B|A') = 3/5Use Bayes’ Theorem to find P(A|B).According to Bayes’ Theorem, the probability of event A, given that event B has occurred, is Р(A) :
P(A) = 2/3, P(A') = 1/3, P(B|A) = 1/5, and P(B|A') = 1/2Use Bayes’ Theorem to find P(A|B).According to Bayes’ Theorem, the probability of event A, given that event B has occurred, is Р(A) :
Research has shown that approximately 1 woman in 600 carries a mutation of the BRCA1 gene. About 60% of women with this mutation develop breast cancer. Find the probability that a randomly selected
Find the probability of randomly selecting a school with 300 or more students.Use the pie chart at the left, which shows the percent distribution of the number of students in U.S. public schools in a
Use the frequency histogram to(a) Determine the number of classes.(b) Estimate the greatest and least frequencies.(c) Determine the class width.(d) Describe any patterns with the data. Roller Coaster
Use the frequency histogram to(a) Determine the number of classes.(b) Estimate the greatest and least frequencies.(c) Determine the class width.(d) Describe any patterns with the data. Employee
Use technology to create(a) A stem-and-leaf plot,(b) A dot plot,(c) A pie chart,(d) A frequency histogram, (e) An ogive for the data. Which graph displays the data best? Explain. 64 46 40 55 70
Use a scatter plot to display the data shown in the table at the left. The data represent the numbers of students per teacher and the average teacher salaries (in thousands of dollars) of 10 school
Use a pie chart to display the data, which represent the number of men’s New York City Marathon winners from each country through 2016.Organize the data using the indicated type of graph. Describe
Use a pie chart to display the data, which represent the number of men’s New York City Marathon winners from each country through 2016. United States 15 Tanzania 1 Great Britain 1 Brazil Italy
Use a stem-and-leaf plot that has two rows for each stem to display the data, which represent the numbers of electoral votes for each of the 50 states.Organize the data using the indicated type of
Match the plot with the description of the sample. 5 10 15 20 25 30 35 40
What is an advantage of using a stem-and-leaf plot instead of a histogram? What is a disadvantage?
The letters A, B, and C are marked on the horizontal axis. Describe the shape of the data. Then determine which is the mean, which is the median, and which is the mode. Justify your answers. Sick
Number of classes: 6Data set: The results of rolling a six-sided die 30 timesConstruct a frequency distribution and a frequency histogram for the data set using the indicated number of classes.
For the month of April, a checking account has a balance of $523 for 24 days, $2415 for 2 days, and $250 for 4 days. What is the account’s mean daily balance for April?Find the weighted mean of the
The scores and their percents of the final grade for an archaeology student are shown below. What is the student’s mean score?Find the weighted mean of the data. Score Percent of final grade
Without performing any calculations, determine which measure of central tendency best represents the graphed data. Explain your reasoning. Body Mass Indexes (BMI) of People in a Gym 18 20 22 24 26 28
Without performing any calculations, determine which measure of central tendency best represents the graphed data. Explain your reasoning. Heart Rates of a Sample of Adults 45 40 35 30 25 20 15 10 5
Without performing any calculations, determine which measure of central tendency best represents the graphed data. Explain your reasoning. Heights of Players on Two Opposing Volleyball Teams 7 5 3 2
Without performing any calculations, determine which measure of central tendency best represents the graphed data. Explain your reasoning. Heights of Players on Two Opposing Volleyball Teams 7 5 3 2
Without performing any calculations, determine which measure of central tendency best represents the graphed data. Explain your reasoning. How Often Do You Change Jobs? 1250- 1000 - 750- 500 250 -
Identify any clusters, gaps, or outliers. Model Year 2017 Hybrid Electric Cars 5 1 600 1200 Annual fuel cost (in dollars) 2700 3000 Frequency 900 1500 1800 2100 2400
The class levels of 25 students in a physics courseFreshman: 2 Junior: 10Sophomore: 5 Senior: 8Find the mean, the median, and the mode of
The numbers of weeks the 33 longest leading Hot 100 songs remained at number 1 as of November 19, 2016:Find the mean, the median, and the mode of the data, if possible. If any measure cannot be found
The durations (in minutes) of power failures at a residence in the last 10 yearsFind the mean, the median, and the mode of the data, if possible. If any measure cannot be found or does not represent
The lengths (in words) of seven articles from The New York Post (Source: The New York Post)650 1242 788 1462 662 709
The numbers of credits being taken by a sample of 14 full-time college students for a semesterFind the mean, the median, and the mode of the data, if possible. If any measure cannot be found or does
Determine whether the approximate shape of the distribution in the histogram is symmetric, uniform, skewed left, skewed right, or none of these. Justify your answer. 16 12 8- 4 52.5 62.5 72.5 82.5
Determine whether the approximate shape of the distribution in the histogram is symmetric, uniform, skewed left, skewed right, or none of these. Justify your answer. 15 12 6. 3- 85 95 105 115 125 135
Determine whether the approximate shape of the distribution in the histogram is symmetric, uniform, skewed left, skewed right, or none of these. Justify your answer. 22 20 18 16 14 12 10 4 2 25,000
Mean is not representative of a typical number in the data set.Construct the described data set. The entries in the data set cannot all be the same.
The English statistician Karl Pearson (1857–1936) introduced a formula for the skewness of a distribution.Most distributions have an index of skewness between -3 and 3. When P > 0, the data are
Sample annual salaries (in thousands of dollars) for employees at a company are listed.(a) Find the sample mean and the sample standard deviation.(b) Each employee in the sample receives a $1000
Sample annual salaries (in thousands of dollars) for employees at a company are listed.(a) Find the sample mean and the sample standard deviation.(b) Each employee in the sample receives a 5% raise.
The mean speed of a sample of vehicles along a stretch of highway is 67 miles per hour, with a standard deviation of 4 miles per hour. Estimate the percent of vehicles whose speeds are between 63
The ages (in years) of a random sample of students in a campus dining hallFind the range, mean, variance, and standard deviation of the sample data set. 19 20 17 19 17 21 23 21 17 17 19 19 17 20 23
Find a real-life data set and use the techniques of Chapter 2, including graphs and numerical quantities, to discuss the center, variation, and shape of the data set. Describe any patterns.
Design a study for some subject that is of interest to you. Answer parts (a)–(d) of Exercise 35 for this study.
Design a study for some subject that is of interest to you. Answer parts (a)–(d) of Exercise 35 for this study.