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A parent group examines 25 randomly selected PG-13 movies and 25 randomly selected PG movies, records the number of sexual innuendos and curse words that occur in each, and then compares the number of sexual innuendos and curse words between the two movie ratings?

Determine whether the study depicts an observational study or a designed experiment.

A sample of 504 patients in early stages of Alzheimer’s disease is divided into two groups. One group receives an experimental drug; the other receives a placebo. The advance of the disease in the patients from the two groups is tracked at 1-month intervals over the next year?

Determine whether the study depicts an observational study or a designed experiment.

On election day, a pollster for Fox News positions herself outside a polling place near her home and asks the first 50 voters leaving the facility to complete a survey?

Determine the type of sampling used.

An Internet service provider randomly selects 15 residential blocks from a large city and surveys every household in these 15 blocks to determine the number that would use a high-speed Internet service?

Determine the type of sampling used.

Thirty-five sophomores, 22 juniors, and 35 seniors are randomly selected to participate in a study from 574 sophomores, 462 juniors, and 532 seniors at a certain high school?

Determine the type of sampling used.

Officers for the Department of Motor Vehicles pull aside every 40th tractor trailer passing through a weigh station, starting with the 12th, for an emissions test?

Determine the type of sampling used.

Fill in the blank

1. A(n) ___________ is a person or object that is a member of the population being studied?

2. _______ statistics consists of organizing and summarizing information collected, while _______ statistics uses methods that generalize results obtained from a sample to the population and measure the reliability of the results?

3. A(n)___________ is a numerical summary of a sample.
A(n)___________ is a numerical summary of a population?

4. ____________  are the characteristics of the individuals of the population being studied?

Determine whether the underlined value is a parameter or a statistic.

1. Following the 2014 national midterm election, 18% of the governors of the 50 United States were female. 

2. The average score for a class of 28 students taking a calculus midterm exam was 72%.

3. In a national survey of 1300 high school students (grades 9 to 12), 32% of respondents reported that someone had bullied them at school. 

4. In a national survey on substance abuse, 9.6% of respondents aged 12 to 17 reported using illicit drugs within the past month.

5. Ty Cobb is one of Major League Baseball’s greatest hitters of all time, with a career batting average of 0.366. 

6. Only 12 men have walked on the moon. The average time these men spent on the moon was 43.92 hours. 

7. A study of 6076 adults in public rest rooms (in Atlanta, Chicago, New York City, and San Francisco) found that 23% did not wash their hands before exiting.

8. Interviews of 100 adults 18 years of age or older, conducted nationwide, found that 44% could state the minimum age required for the office of U.S. president.

A farmer interested in the weight of his soybean crop randomly samples 100 plants and weighs the soybeans on each plant?

A research objective is presented. For each, identify the population and sample in the study.

Every year the U.S. Census Bureau releases the Current Population Report based on a survey of 50,000 households. The goal of this report is to learn the demographic characteristics, such as income, of all households within the United States?

A research objective is presented. For each, identify the population and sample in the study.

Contrast the differences between qualitative and quantitative variables?

A community college notices that an increasing number of full-time students are working while attending the school. The administration randomly selects 128 students and asks how many hours per week each works?

A research objective is presented. For each, identify the population and sample in the study.

The age of a person is commonly considered to be a continuous random variable. Could it be considered a discrete random variable instead? Explain.

Explain why it would be unlikely to use a designed experiment to answer the research question posed in Example 3?

The American Cancer Society is beginning a study to learn why some people never get cancer. To take part in the study, a person must be 30–65 years of age and never had cancer. The study requires that the participants fill out surveys about their health and habits and give blood samples and waist measurements. These surveys must be filled out every two years. The study is expected to last for the next 20 years?

Determine whether the study depicts an observational study or an experiment.

Rats with cancer are divided into two groups. One group receives 5 milligrams (mg) of a medication that is thought to fight cancer, and the other receives 10 mg. After 2 years, the spread of the cancer is measured?

Determine whether the study depicts an observational study or an experiment.

Seventh-grade students are randomly divided into two groups. One group is taught math using traditional techniques;the other is taught math using a reform method. After 1 year, each group is given an achievement test to compare proficiency?

Determine whether the study depicts an observational study or an experiment.

A study in which balding men were compared with non-balding men at one point in time found that balding men were 70% more likely to have heart disease?

Determine whether the study depicts an observational study or an experiment.

A survey is conducted asking 400 people, “Do you prefer Coke or Pepsi?”

Determine whether the study depicts an observational study or an experiment.

Two hundred people are asked to perform a taste test in which they drink from two randomly placed, unmarked cups and asked which drink they prefer?

Determine whether the study depicts an observational study or an experiment.

Sixty patients with carpal tunnel syndrome are randomly divided into two groups. One group is treated weekly with both acupuncture and an exercise regimen. The other is treated weekly with the exact same exercise regimen, but no acupuncture. After 1 year, both groups are questioned about their level of pain due to carpal tunnel syndrome.

Determine whether the study depicts an observational study or an experiment.

What does it mean when sampling is done without replacement?

To determine the prevalence of human growth hormone (HGH) use among high school varsity baseball players, the State Athletic Commission randomly selects 50 high schools. All members of the selected high schools’ varsity baseball teams are tested for HGH?

Identify the type of sampling used.

Describe a circumstance in which stratified sampling would be an appropriate sampling method?

Which sampling method does not require a frame?

A(n) _____ sample is obtained by dividing the population into groups and selecting all individuals from within a random sample of the groups?

A(n) _____ sample is obtained by dividing the population into homogeneous groups and randomly selecting individuals from each group?

To estimate the percentage of defects in a recent manufacturing batch, a quality-control manager at Intel selects every 8th chip that comes off the assembly line starting with the 3rd until she obtains a sample of 140 chips?

Identify the type of sampling used.

To determine customer opinion of its boarding policy, Southwest Airlines randomly selects 60 flights during a certain week and surveys all passengers on the flights?

Identify the type of sampling used.

A member of Congress wishes to determine her constituency’s opinion regarding estate taxes. She divides her constituency into three income classes: low-income households, middle- income households, and upper-income households. She then takes a simple random sample of households from each income class?

Identify the type of sampling used.

In an effort to identify whether an advertising campaign has been effective, a marketing firm conducts a nationwide poll by randomly selecting individuals from a list of known users of the product?

Identify the type of sampling used.

A radio station asks its listeners to call in their opinion regarding the use of U.S. forces in peacekeeping missions?

Identify the type of sampling used.

A farmer divides his orchard into 50 subsections, randomly selects 4, and samples all the trees within the 4 subsections to approximate the yield of his orchard?

Identify the type of sampling used.

A college official divides the student population into five classes: freshman, sophomore, junior, senior, and graduate student. The official takes a simple random sample from each class and asks the members’ opinions regarding student services?

Identify the type of sampling used.

A survey regarding download time on a certain website is administered on the Internet by a market research firm to anyone who would like to take it?

Identify the type of sampling used.

The presider of a guest-lecture series at a university stands outside the auditorium before a lecture begins and hands every fifth person who arrives, beginning with the third, a speaker evaluation survey to be completed and returned at the end of the program?

Identify the type of sampling used.

To determine his DSL Internet connection speed, Shawn divides up the day into four parts: morning, midday, evening, and late night. He then measures his Internet connection speed at 5 randomly selected times during each part of the day?

24 Hour Fitness wants to administer a satisfaction survey to its current members. Using its membership roster, the club randomly selects 40 club members and asks them about their level of satisfaction with the club?

Identify the type of sampling used.

To obtain students’ opinions about proposed changes to course registration procedures, the administration of a small college asked for faculty volunteers who were willing to administer a survey in one of their classes. Twenty-three faculty members volunteered. Each faculty member gave the survey to all the students in one course of their choosing. Would this sampling method be considered a cluster sample? Why or why not?

Target wants to open a new store in the village of Lock port. Before construction, Target’s marketers want to obtain some demographic information regarding the area under consideration. Design a sampling method to obtain the individuals in the sample. Be sure to support your choice?

The county sheriff wants to determine if a certain highway has a high proportion of speeders traveling on it. Design a sampling method to obtain the individuals in the sample. Be sure to support your choice?

A pharmaceutical company wants to conduct a survey of 30 individuals who have high cholesterol. The company has obtained a list from doctors throughout the country of 6600 individuals who are known to have high cholesterol. Design a sampling method to obtain the individuals in the sample. Be sure to support your choice?

What does it mean when a part of the population is underrepresented?

Surveys tend to suffer from low response rates. Based on past experience, a researcher determines that the typical response rate for an e-mail survey is 40%. She wishes to obtain a sample of 300 respondents, so she e-mails the survey to 1500 randomly selected e-mail addresses. Assuming the response rate for her survey is 40%, will the respondents form an unbiased sample? Explain

Consider this question from a recent Gallup poll:
Which of the following approaches to solving the nation’s energy problems do you think the U.S. should follow right now—[ROTATED: emphasize production of more oil, gas and coal supplies (or) emphasize more conservation by consumers of existing energy supplies]?
Why is it important to rotate the two choices presented in the question?

In the federal government’s Current Population Survey, the response rate for 20- to 29 year olds is 85%; for individuals at least 70 years of age it is 99%. Why do you think this is?

During every election, pollsters conduct exit polls to help determine which candidate people voted for. During the 2004 presidential election, pollsters incorrectly predicted John Kerry the winner over George Bush. When asked how this error could have happened, the pollsters cited interviewer error due to the fact that many of the interviewers were young, only young voters agreed to be interviewed, and young voters tended to favor Kerry. Plus, young interviewers tend to make more data-entry mistakes. In addition, the method of selecting individuals to be interviewed led to selecting a higher proportion of female voters, and Kerry was favored by females. In some precincts, interviewers were denied access to voters. Research the 2004 exit polling fiasco. Explain which non sampling errors led to the incorrect conclusion regarding the 2004 election?

Name two biases that led to the Literary Digest making an incorrect prediction in the presidential election of 1936?

Research the polling done by George Gallup in the 1936 presidential election. Write a report on your findings and include information about the sampling technique and sample size. Next, research the polling done by Gallup for the 1948 presidential election. Did Gallup accurately predict the outcome of the election? What lessons were learned by Gallup?

What are some solutions to non response?

Discuss the benefits of having trained interviewers?

What are the advantages of having a presurvey when constructing a questionnaire that has closed questions?

Discuss the pros and cons of telephone interviews that take place during dinner time in the early evening?

Discuss why the order of questions or choices within a questionnaire are important in sample surveys.

What is replication in an experiment?

Explain the difference between a single-blind and a double-blind experiment?

A(n) ______ ______ design is one in which each experimental unit is randomly assigned to a treatment.

A(n) ______ ______ design is one in which the experimental units are paired up.


1. True or False: Observational studies are used to determine causality between explanatory and response variables.
2. True or False: Generally, the goal of an experiment is to determine the effect that treatments will have on the response variable.

An engineer wants to determine the effect of temperature on battery voltage. In particular, he is interested in determining if there is a significant difference in the voltage of the batteries when exposed to temperatures of 90°F, 70°F, and 50°F. Help the engineer design the experiment. Include a diagram to illustrate your design?

Search a newspaper, magazine, or other periodical that describes an experiment. Identify the population, experimental unit, response variable, treatment, factors, and their levels?

In their book SuperFreakonomics, authors Steven Levitt and Stephen Dubner describe the research of behavioral economist John List. List recruited customers and dealers at a baseball-card show to participate in an experiment in which the customer would state how much he was willing to pay for a single baseball card. The prices ranged from $4 (lowball) to $50 (premium card). The dealer would then give the customer a card that was supposed to correspond to the offer price. In this setting, the dealer could certainly give the buyer a card worth less than the offer price, but this rarely happened. The card received by the buyer was close in value to the price offered. Next, List went to the trading floor at the show and again recruited customers. But this time the customers approached dealers at their booth. The dealers did not know they were being  atched. The scenario went something like this: as the customer approached the dealer’s booth, he would say, “Please give me the best Derek Jeter card you can for $20.” In this scenario, the dealers consistently ripped off the customers by giving them cards worth much less than the offer price. In fact, the dealers who were the worst offenders were the same dealers who refused to participate in List’s study. Do you believe that individuals who volunteer for experiments are scientific do-gooders? That is, do you believe that in designed experiments subjects strive to meet the expectations of the researcher? In addition, do you believe that results of experiments may suffer because many experiments require individuals to volunteer, and individuals who are not dogooders do not volunteer for studies? Now, explain why control groups are needed in designed experiments and the role they can play in neutralizing the impact of scientific do-gooders.

Brand name of a pair of running shoes

Classify the variable as qualitative or quantitative. If the variable is quantitative, state whether it is discrete or continuous.

In the 2015 NCAA Football Championship Game, quarterback Cardale Jones completed 70% of his passes for a total of 242 yards?

Determine whether the underlined value is a parameter or a statistic.

Define raw data in your own words?

A frequency distribution lists the __________ of occurrences of each category of data, while a relative frequency distribution lists the __________ of occurrences of each category of data.

The following table lists the presidents of the United States (as of May, 2016) and their state of birth.


(a) Construct a frequency bar graph for state of birth.
(b) Which state has yielded the most presidents?
(c) Explain why the answer obtained in part (b) may be misleading.

When should relative frequencies be used when comparing two data sets? Why?

Consider the information in the chart shown below, which is in the USA Today style of graph. Could the information provided be organized into a pie chart? Why or why not?

Fill in the blanks.

1. The categories by which data are grouped are called ________________ .
2. The ___________ class limit is the smallest value within the class and the class limit is the largest value within the class.
3. The ___________ is the difference between consecutive lower class limits.

What does it mean if a distribution is said to be “skewed left”?

Use the data in Problem 24. What percentage of earthquakes registered 4.0 to 4.9? What percentage of earthquakes registered 4.9 or less?

(a) A relative frequency distribution,

(b) A frequency histogram,

(c) A relative frequency histogram for the given data. Then answer the questions that follow.


Refer in Problem 24,

Magnitude __________________ Number
0–0.9 ........................................... 3371
1.0–1.9 ....................................... 3400
2.0–2.9 ....................................... 1237
3.0–3.9 ......................................... 286
4.0–4.9 ....................................... 1045
5.0–5.9 ......................................... 121
6.0–6.9 ............................................ 7
7.0–7.9 ............................................ 2

The following data represent the number of grams of fat in breakfast meals offered at McDonald’s.


(a) construct a stem-and-leaf plot and
(b) describe the shape of the distribution.

Nielsen/NetRatings measures the amount of time an individual spends viewing a specific web page. The following data represent the amount of time, in seconds, a random sample of 40 individuals spent viewing a web page. Decide on an appropriate graphical summary and create the graphical summary. Write a few sentences that describe the data. Be sure to include in your description any interesting features the data may exhibit.

Why shouldn’t classes overlap when summarizing continuous data in a frequency or relative frequency distribution?

Describe the situations in which it is preferable to use relative frequencies over frequencies when summarizing quantitative data?

What type of variable is required when drawing time-series plots? What is the purpose behind drawing a time-series plot?

The following graph appears on the Wikipedia website. The intention of the graph is to display the ages of U.S. presidents on Inauguration Day. Explain any problems you see with the graph.

What does it mean if a statistic is resistant? 

The ....................... represents the number of standard deviations an observation is from the mean.

The Federal Bureau of Investigation classifies various larcenies. The data in the next column represent the type of larcenies based on a random sample of 15 larcenies. What is the mode type of larceny?

The ........................ of a data set is a value such that k percent of the observations are less than or equal to the value.

..................... divide data sets into fourths.

A histogram of a set of data indicates that the distribution of the data is skewed right. Which measure of central tendency will likely be larger, the mean or the median? Why?

The ................... is the range of the middle 50% of the observations in a data set.

True or False: A data set will always have exactly one mode.

According to the National Center for Health Statistics, a 19-year-old female whose height is 67.1 inches has a height that is at the 85th percentile. Explain what this means.

According to the National Center for Health Statistics, a 10-year-old male whose height is 53.5 inches has a height that is at the 15th percentile. Explain what this means.

The distribution of income tends to be skewed to the right. Suppose you are running for a congressional seat and wish to portray that the average income in your district is low. Which measure of central tendency, the mean or the median, would you report? Why?

Answer the following based on the histograms shown below.


(a) Which measure of central tendency would you recommend reporting for the data whose histogram is shown in Figure I? Why?
(b) Which one has more dispersion? Explain.


Explain how the standard deviation measures dispersion. In your explanation, include a discussion of deviation about the mean.

Which box plot likely has the data with a larger standard deviation? Why?

I.

II.

Write a paragraph that explains the meaning of percentiles.

Suppose you received the highest score on an exam. Your friend scored the second-highest score, yet you both were in the 99th percentile. How can this be?

When outliers are discovered, should they always be removed from the data set before further analysis?

Mensa is an organization designed for people of high intelligence. One qualifies for Mensa if one’s intelligence is measured at or above the 98th percentile. Explain what this means.

Explain the advantage of using z-scores to compare observations from two different data sets.

A researcher with the Department of Energy wants to determine the mean natural gas bill of households throughout the United States. He knows the mean natural gas bill of households for each state, so he adds together these 50 values and divides by 50 to arrive at his estimate. Is this a valid approach? Why or why not?

In January 2016, the mean amount of money lost per visitor to a local riverboat casino was $135. Do you think the median was more than, less than, or equal to this amount? Why?

Match the histograms in the next column to the summary statistics given.

Are any of the measures of dispersion mentioned in this section resistant? Explain.

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