Elementary Statistics ( 3rd International Edition ) Isbn:9781260092561
3rd Edition
ISBN: 9781259969454
Author: William Navidi Prof.; Barry Monk Professor
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 1.3, Problem 30E
Another Salk Vaccine Trial: Another study of the Salk vaccine, conducted at the same time as the trial described in Exercise 29, used a different design. In this study, approximately 350,000 second graders were invited to participate. About 225,000 did so, and the other 125,000 refused. All of the participating second graders received the vaccine. The control group consisted of approximately 725,000 first and third graders.
They were not given any placebo, so no consent was necessary.
- Was this a randomized experiment?
- Was it double-blind?
- The treatment group consisted of children who had consent to participate. The control group consisted of all first and third graders. It turned out that the results of this study seriously underestimated the effectiveness of the vaccine. Use the information provided in Exercise 29(c) to explain why.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
state whether the investigation in question is an observational study or a designed experiment. Justify your answer in each case.
The Salk Vaccine. In the 1940s and early 1950s, the public was greatly concerned about polio. In an attempt to prevent this disease, Jonas Salk of the University of Pittsburgh developed a polio vaccine. In a test of the vaccine’s efficacy, involving nearly 2 million grade-school children, half of the children received the Salk vaccine; the other half received a placebo, in this case an injection of salt dissolved in water. Neither the children nor the doctors performing the diagnoses knew which children belonged to which group, but an evaluation center did. The center found that the incidence of polio was far less among the children inoculated with the Salk vaccine. From that information, the researchers concluded that the vaccine would be effective in preventing polio for all U.S. school children; consequently, it was made available for general use.
The District of Columbia Opportunity Scholarship Program was created by Congress to provide tuition vouchers to low-income parents who want their child to attend a private school.
In 2012–2014, a treatment group of 995 students were randomly selected to receive a tuition
voucher, while a control group of 776 students did not receive vouchers. One year later, the
students were given a standardized reading test. The average score of the students in the treatment group was 601.78 with a standard deviation of 52.65; the average score of the control group was 605.78 with a standard deviation of 55.73.
At the level of significance alpha = 0.01, do we have enough evidence to conclude that the average
reading score of students who receive a tuition voucher to attend private school is lower than the average reading score of students who do not receive a tuition voucher?
Cocaine addiction is very hard to break. Even among addicts trying hard to break the addiction, relapse is common. (A relapse is when a person trying to break out of the addiction fails and uses cocaine again.) A study is conducted to investigate the effectiveness of two drugs, desipramine and lithium, in the treatment of cocaine addiction. The subjects in the six-week study were cocaine addicts seeking treatment. The 72 subjects were randomly assigned to one of three groups (desipramine, lithium, or a placebo, with 24 subjects in each group) and the study was double-blind.
Relapse
No relapse
Desipramine
10
14
Lithium
18
6
Placebo
20
4
1.We are interested in knowing whether there was a difference in the proportion of relapse between the two drugs.
Write the null and alternative hypotheses that would help determine an answer to our research their question. (You are writing equations, not words.)
H0: HA:
Define the symbol(s) you used in your…
Chapter 1 Solutions
Elementary Statistics ( 3rd International Edition ) Isbn:9781260092561
Ch. 1.1 - In Exercises 7—12, fill in each blank with the...Ch. 1.1 - In Exercises 7—12, fill in each blank with the...Ch. 1.1 - In Exercises 7—12, fill in each blank with the...Ch. 1.1 - In Exercises 7—12, fill in each blank with the...Ch. 1.1 - In Exercises 7—12, fill in each blank with the...Ch. 1.1 - In Exercises 7—12, fill in each blank with the...Ch. 1.1 - In Exercises 13—16, determine whether the...Ch. 1.1 - In Exercises 13—16, determine whether the...Ch. 1.1 - In Exercises 13—16, determine whether the...Ch. 1.1 - In Exercises 13—16, determine whether the...
Ch. 1.1 - In Exercises 17—20, determine whether the number...Ch. 1.1 - In Exercises 17—20, determine whether the number...Ch. 1.1 - In Exercises 17—20, determine whether the number...Ch. 1.1 - In Exercises 17—20, determine whether the number...Ch. 1.1 - Exercises 21—24 refer to the population of...Ch. 1.1 - Exercises 21—24 refer to the population of...Ch. 1.1 - Exercises 21—24 refer to the population of...Ch. 1.1 - Exercises 21—24 refer to the population of...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - In Exercises 25—36, identify the kind of sample...Ch. 1.1 - Computer network: Every third day, a computer...Ch. 1.1 - Smartphone apps: A smartphone app produces a...Ch. 1.1 - Youre giving me a headache: A pharmaceutical...Ch. 1.1 - Pay more for recreation? The director of the...Ch. 1.1 - Voter preferences: A pollster wants to sample 500...Ch. 1.1 - Quality control: Products come off an assembly...Ch. 1.1 - On-site day care: A large company wants to sample...Ch. 1.1 - The tax man cometh: The Internal Revenue Service...Ch. 1.1 - Draw a sample: Imagine that you are asked to...Ch. 1.1 - A systematic sample is a cluster sample: Explain...Ch. 1.2 - In Exercises 5—10, fill in each blank with the...Ch. 1.2 - In Exercises 5—10, fill in each blank with the...Ch. 1.2 - In Exercises 5—10, fill in each blank with the...Ch. 1.2 - In Exercises 5—10, fill in each blank with the...Ch. 1.2 - In Exercises 5—10, fill in each blank with the...Ch. 1.2 - In Exercises 5—10, fill in each blank with the...Ch. 1.2 - In Exercises 11—14, determine whether the...Ch. 1.2 - In Exercises 11—14, determine whether the...Ch. 1.2 - In Exercises 11—14, determine whether the...Ch. 1.2 - In Exercises 11—14, determine whether the...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 15—24, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 25—32, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - In Exercises 33—40, determine whether the data...Ch. 1.2 - Music Videos: Following are the most-viewed videos...Ch. 1.2 - More Videos: The following table presents the...Ch. 1.2 - Hows the economy? A poll conducted by the American...Ch. 1.2 - Global warming: A recent Pew poll asked people...Ch. 1.2 - Graphic Novels: According to Time magazine, some...Ch. 1.2 - Watch sour language: According to Merriam Webster...Ch. 1.2 - Top ten video games: According to Wikipedia, the...Ch. 1.2 - At the movies: The following table provides...Ch. 1.2 - What do the numbers mean? A survey is administered...Ch. 1.3 - In Exercises 5—10, fill in each blank with the...Ch. 1.3 - In Exercises 5—10, fill in each blank with the...Ch. 1.3 - In Exercises 5—10, fill in each blank with the...Ch. 1.3 - In Exercises 5—10, fill in each blank with the...Ch. 1.3 - In Exercises 5—10, fill in each blank with the...Ch. 1.3 - In Exercises 5—10, fill in each blank with the...Ch. 1.3 - In Exercise 11—16, determine whether the...Ch. 1.3 - In Exercise 11—16, determine whether the...Ch. 1.3 - In Exercise 11—16, determine whether the...Ch. 1.3 - In Exercise 11—16, determine whether the...Ch. 1.3 - In Exercise 11—16, determine whether the...Ch. 1.3 - In Exercise 11—16, determine whether the...Ch. 1.3 - To determine the effectiveness of a new pain...Ch. 1.3 - A medical researcher wants to determine whether...Ch. 1.3 - A medical researcher wants to determine whether...Ch. 1.3 - An agricultural scientist wants to determine the...Ch. 1.3 - Air pollution and colds: A scientist wants to...Ch. 1.3 - Cold medications: A scientist wants to determine...Ch. 1.3 - Taxicabs and crime: A sociologist discovered that...Ch. 1.3 - Recovering from heart attacks: In a study of...Ch. 1.3 - Eat your vegetables: In an observational study,...Ch. 1.3 - Vocabulary and height: A vocabulary test was given...Ch. 1.3 - Secondhand smoke: A recent study compared the...Ch. 1.3 - Pollution in China: In a recent study, Z. Zhao and...Ch. 1.3 - The Salk Vaccine Trial: In 1954, the first vaccine...Ch. 1.3 - Another Salk Vaccine Trial: Another study of the...Ch. 1.3 - Smoking and health: A study was performed by the...Ch. 1.3 - Alcohol and liver disease: It is known that...Ch. 1.4 - In Exercises 3—5, fill in each blank with the...Ch. 1.4 - In Exercises 3—5, fill in each blank with the...Ch. 1.4 - In Exercises 3—5, fill in each blank with the...Ch. 1.4 - In Exercises 6—8, determine whether the...Ch. 1.4 - In Exercises 6—8, determine whether the...Ch. 1.4 - In Exercises 6—8, determine whether the...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - In Exercises 9—16, specify the type of bias...Ch. 1.4 - Nuclear power, anyone? In a survey conducted by...Ch. 1.4 - Whos calling, please? Random-digit dialing is a...Ch. 1.4 - Whos calling, please? Many polls are conducted...Ch. 1.4 - Order of choices: When multiple-choice questions...Ch. 1.4 - Literary Digest poll: In the 1936 presidential...Ch. 1 - Provide an example of a qualitative variable and...Ch. 1 - Is the name of your favorite author a qualitative...Ch. 1 - Prob. 3CQCh. 1 - Prob. 4CQCh. 1 - True or false: Ideally, a sample should represent...Ch. 1 - Prob. 6CQCh. 1 - Prob. 7CQCh. 1 - Prob. 8CQCh. 1 - Prob. 9CQCh. 1 - Prob. 10CQCh. 1 - Prob. 11CQCh. 1 - Prob. 12CQCh. 1 - In analyzing the course grades of students in an...Ch. 1 - Prob. 14CQCh. 1 - Prob. 15CQCh. 1 - Prob. 1RECh. 1 - Prob. 2RECh. 1 - Prob. 3RECh. 1 - Prob. 4RECh. 1 - In Exercises 5—8, identify the kind of sample...Ch. 1 - Prob. 6RECh. 1 - Prob. 7RECh. 1 - Prob. 8RECh. 1 - Fluoride and tooth decay: Researchers examine the...Ch. 1 - Better gas mileage: A taxi company in a large city...Ch. 1 - Prob. 11RECh. 1 - Prob. 12RECh. 1 - Prob. 13RECh. 1 - Prob. 14RECh. 1 - Prob. 15RECh. 1 - Describe the difference between a stratified...Ch. 1 - Prob. 2WAICh. 1 - Describe circumstances under which each of the...Ch. 1 - Suppose that you were asked to collect some...Ch. 1 - Prob. 5WAICh. 1 - What are the primary differences between a...Ch. 1 - What are the advantages of a double-blind study?...Ch. 1 - Prob. 8WAICh. 1 - Prob. 9WAICh. 1 - Air pollution is a serious problem in many places....Ch. 1 - Prob. 2CSCh. 1 - Air pollution is a serious problem in many places....Ch. 1 - Air pollution is a serious problem in many places....Ch. 1 - Air pollution is a serious problem in many places....Ch. 1 - Air pollution is a serious problem in many places....Ch. 1 - Is there a large difference between the percentage...Ch. 1 - Explain why the percentage of high-exposure people...Ch. 1 - Explain why the percentage of low-exposure people...Ch. 1 - As the weather sets warmer. PM goes down because...Ch. 1 - It is generally the case in epidemiologic studies...Ch. 1 - Rather than send out questionnaires, the...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.Similar questions
- What is an experiment?arrow_forwardWhen a police officer responds to a call for help in a case of spousal abuse, what should the officer do? A randomized controlled experiment in Charlotte, North Carolina, studied three police responses to spousal abuse: advise and possibly separate the couple, issue a citation to the offender, and arrest the offender. The effectiveness of the three responses was determined by re-arrest rates. The table below shows these rates. Assigned treatment Number of Arrest Citation Advise/separate subsequent arrests 0 175 181 187 1 36 33 24 2 2 7 3 1 1 0 4 0 2 What is the proportion of all cases in which the assigned treatment was "Advise/separate"? 0.33 0.84 0.88 0.29arrow_forwardDetermine whether the results appear to have statistical significance, and also determine whether the results appear to have practical significance. One of a botanist's hybridization experiments with peas yielded 488 offspring with 125 of those peas (or 26%) having yellow pods. According to genetic theory, 25% of the offspring peas should have yellow pods. According to genetic theory, 122 of the 488 peas would have yellow pods. The difference between the actual number of peas with yellow pods and the expected number of peas with yellow pods is pea(s). This difference does not appear to be statistically significant. (Type whole numbers.) Does the result have practical significance? This difference does not appear to have practical significance, because the difference between the actual number of peas with yellow pods and the expected number of peas with yellow pods is very small compared to thearrow_forward
- Green Tea and Prostate Cancer A preliminary study suggests a benefit from green tea for those at risk of prostate cancer. The study involved 60 men with PIN lesions, some of which turn into prostate cancer. Half the men, randomly determined, were given 600 mg a day of a green tea extract while the other half were given a placebo. The study was double-blind, and the results after one year are shown in the table below. Treatment Cancer No Cancer Green Tea 1 29 Placebo 9 21 (a) Test at a 5% significant level to see if the sample provide evidence that taking green tea extract reduces the risk of developing prostate cancer. (b) Find 98% confidence interval for the difference between two population proportions of men with PIN lesions who get prostate cancer after taking green tea extract and after taking placebo for a year. Interpret the C.I. result.arrow_forwardIn randomized, double-blind clinical trials of a new vaccine, children were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 123 of 460 subjects in the experimental group (group 1) experienced drowsiness as a side effect. After the second dose, 24 of 106 of the subjects in the control group (group 2) experienced drowsiness as a side effect. Does the evidence suggest that a different proportion of subjects in group 1 experienced drowsiness as a side effect than subjects in group 2 at the a = 0.01 level of significance? Determine the null and alternative hypotheses. Choose the correct answer below. A. Ho: P1 =0 versus Ho: P, #0 B. Ho: P =P2 versus H,: P, P2 The test statistic zo is (Round to two decimal places as needed.)arrow_forwardA school superintendent wants to know the effects of a four week anti-bullying course on high school students. The superintendent randomly selects 200 high school students and randomly assigns 100 high school students to participate in the course. She then assigns the remaining 100 high school students to not participate in the course. At the end of the course, the superintendent will observe the students' behavior in a school setting.Which of the following methods was used in this study? A. experimental study B. randomized experiment C. observational study D. surveyarrow_forward
- You are a senior in the agricultural sciences department of NCSU doing an internship at a local dairy farm. Farmer Bill is an expert dairy farmer but has no background in quantitative decision making. Bill claims that the milk produced by his grass-fed Jersey cattle has higher protein content than the milk made by his grain-fed Jersey cattle. His evidence? He says he can taste the difference. You decide to put Bill's claim to the test. You randomly sample 21 grass-fed Jersey cattle and 18 grain- fed Jersey cattle, independently of one another, and obtain a sample of milk from each cow. Both histograms appear approximately normal. You test Ho : 41 = Hz VS. HA : 1 > Hz, where i is the true mean protein content of milk produced by grass-fed Jersey cattle and µz is that for the grain-fed cattle. Your test statistic is 1.98. Based on this information, which of the following is true ? Select one or more: O a. The sample mean protein content for the milk samples from the grass-fed cattle you…arrow_forwardStudy 1: A study of 300 high school students was done. Half of them were instructed to drink soda every day. The other half was instructed to not drink soda at all. After one month, the half that were drinking soda had gained an average of five pounds more than the half that did not drink soda. a. Is this a controlled study? Why or why not?arrow_forwardYou are a senior in the agricultural sciences department of NCSU doing an internship at a local dairy farm. Farmer Bill is an expert dairy farmer but has no background in quantitative decision making. Bill claims that the milk produced by his grass-fed Jersey cattle has higher protein content than the milk made by his grain-fed Jersey cattle. His evidence? He says he can taste the difference. You decide to put Bill's claim to the test. You randomly sample 21 grass-fed Jersey cattle and 18 grain-fed Jersey cattle, independently of one another, and obtain a sample of milk from each cow. Both histograms appear approximately normal. You test Ho : 4 = H2 VS. HA : H1 > 2. where 4 is the true mean protein content of milk produced by grass-fed Jersey cattle and-u, is that for the grain-fed cattle. Your test statistic is 1.98. Based on this information, which of the following is true ? Select one or more: O a. The sample mean protein content for the milk samples from the grass-fed cattle you…arrow_forward
- Shopping cart abandonment is a major concern for online retailers. This happens when a visitor to the online retailer puts one or more items in their virtual shopping cart but then abandons the cart, leaving the retailer without having made a purchase. To reduce cart abandonment, one online retailer is considering a “pop-up” free shipping offer to visitors who put an item in their virtual shopping cart. The online retailer decided to test the effectiveness of this free shipping offer. During a randomly selected two-week period, 718 visitors to the website placed at least one item in their virtual shopping cart. The retailer offered free shipping to 350 of those visitors; the remainder did not get the offer. Of those who received the free shipping offer, 191 abandoned their carts. Of those who did not receive the offer, 246 abandoned their carts. In the image attached, you will find a 2×2 contingency table with the free shipping offer (Yes/No) by row and cart abandoned (Yes/No) by…arrow_forwardShopping cart abandonment is a major concern for online retailers. This happens when a visitor to the online retailer puts one or more items in their virtual shopping cart but then abandons the cart, leaving the retailer without having made a purchase. To reduce cart abandonment, one online retailer is considering a “pop-up” free shipping offer to visitors who put an item in their virtual shopping cart. The online retailer decided to test the effectiveness of this free shipping offer. During a randomly selected two-week period, 718 visitors to the website placed at least one item in their virtual shopping cart. The retailer offered free shipping to 350 of those visitors; the remainder did not get the offer. Of those who received the free shipping offer, 191 abandoned their carts. Of those who did not receive the offer, 246 abandoned their carts. Complete the contingency table with actual frequencies (not probabilities), including joint and marginal frequencies, using the information…arrow_forwardShopping cart abandonment is a major concern for online retailers. This happens when a visitor to the online retailer puts one or more items in their virtual shopping cart but then abandons the cart, leaving the retailer without having made a purchase. To reduce cart abandonment, one online retailer is considering a “pop-up” free shipping offer to visitors who put an item in their virtual shopping cart. The online retailer decided to test the effectiveness of this free shipping offer. During a randomly selected two-week period, 718 visitors to the website placed at least one item in their virtual shopping cart. The retailer offered free shipping to 350 of those visitors; the remainder did not get the offer. Of those who received the free shipping offer, 191 abandoned their carts. Of those who did not receive the offer, 246 abandoned their carts.Complete the contingency table with actual frequencies (not probabilities), including joint and marginal frequencies, using the information…arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Hypothesis Testing using Confidence Interval Approach; Author: BUM2413 Applied Statistics UMP;https://www.youtube.com/watch?v=Hq1l3e9pLyY;License: Standard YouTube License, CC-BY
Hypothesis Testing - Difference of Two Means - Student's -Distribution & Normal Distribution; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=UcZwyzwWU7o;License: Standard Youtube License