Unit 3 MC Practice
A large company wants to conduct a survey to determine the proportion of its female employees who practice sel defense on a daily basis. 4 of regional offices are randomly selected and all of the women in those offices are surveyed This plan is an example of which type of sampling ?
A cluster random sample
What is the main benefit of using a matched pairs design as opposed to a controlled randomized design?
A matched pairs design reduces variation among different aspects of the subjects
The Watchmen locate 20 pairs of neighborhoodswhere each pair is similar in sizeeconomic status, number of streetlights, number of dogs, number of nosy neighbors, etc One neighborhood in each pair is randomly assigned to have the neighborhood watch program and the does not This is an example of
A matched pairs experiment
The researcher also surveys 250 randomly selected males and asks them the same questionsA scatterplot made with different symbols for male and female data The study done by this researcher is
A observational study
Suppose 100 subjects were asked what their annual income was last year. This is an example of...
A sample but not a stratified sample
The music industry is a huge financial industryWhen a song is played on a radio station, the musicians are entitled to a royalty payment. It would be impossible to listen to every song played on every radio station to determine the royalties due to each musician. InsteadThe American Society of ComposersAuthors, and Publishers (ASCAP) randomly samples radio stations and times of day to listen to the music being played and to determine the royalties due to each musician Which of the following statements is FALSE?
ASCAP's song selection procedure most closely resembles a census.
Suppose a new cancer drug is being tested on 200 male volunteers who have prostate cancer. The researchers decide to use a block design and wish to test the difference between the new drug and a more traditional treatment. what would be an effective variable to block on?
Advancement phase of the cancer.
Variables such as exercise, location and medical treatment are all controlled for. However, the company needs to decide whether to use only a specific breed of dog or include a variety of dogs. What is a statistical advantage of using only one specific breed of dog for this study? A statistical disadvantage?
Advantage: less variability in results Disadvantage: difficult to generalize the results two other breeds
How could one use simulation to determine the number of questions she could answer correctly until she gets one wrong?
Assign digits 0 - 1 to answers correctlyassign digits 2 - 7 to answers incorrectly.
Read the following statements about randomized blocked experiments and matched pair experiments. Which of the following statements is false?
At the end of a randomized block experiment, it is most important to compare the blocks to each other.
Isaac wanted to know the mean number of students in mathematics classes at his small high school What is the best way for him to collect his data?
Census
Ten minutes after the cakes come out of the oven, an assistant measures the height of each cake at its center. The assistant does not know the specific treatment given to any of the cakes he measures. The average height of the cakes in Group B is significantly higher than the average height of the cakes in Group A. This study is flawed because it demonstrates
Confounding
Suppose a worker in the school cafeteria wants to know if the students feel the cafeteria is offering enough healthy items on the daily menu . What could be a useful variable to stratify for the purposes of this study ?
Gender of respondents
Characteristics of a well designed experiment- which of the following statements are true?
I and II ONLY
Features of a well-designed survey- which of the following statements is true?
I only
If the random digits provided are used to select the SRS, which of the following students will NOT be included in the SRS?
Irma.
Which of the following scenarios describes a census?
Margeaux wants to know the average age of the people who belong to her book club. To gather data, she consults the membership list which consists of 40 individuals. She then contacts each of these 40 people who provide her with their age so that she can find the average.
Suppose that a study of a group of randomly selected people found that those who eat breakfast daily weigh less than those who do not eat breakfast daily What is a possible lurking variable in this study?
People who eat breakfast are more likely to exercise
Which of the following is not required in order for this to be a well designed survey?
The network should secure that every possible sub group of 180 customers should have the same chance of being chosen as the sample.
The local highway commission draws a random sample of 150 adults from the driver's license database to ask "Would you support raising taxes 1% to pay for a new 10 mile expressway?" This survey will most likely suffer from
Undercoverage bias because taxpayers who do not have a driver's license will not be able to contribute their opinions .
There are three factors and 18 treatments. What is a type of bias present here? Furthermore, is the true population proportion who support this initiate higher, lower, or about the same as the people proportion?
Undercoverage bias; population proportion is lower.
A town committee is thinking about investing $200,000 for lighting the baseball fields. The first selectman of the town wants to survey 500 citizens of the town to see what they think. Which of the following will produce a simple random sample?
Using latest census data from the town, numbering the citizens, and using a random number generator to select 500 citizens.
Which of the following best describes how to create the blocks?
Within each block subjects should be as similar as possible with respect to their language learning abilities.
Which of the following experiments could best be performed double- blind?
Determine if aspirin or Tylenol reduces the intensity of pain more for a patient.
After noticing that you are lacking in extracurriculars, you decide to run for class president. Being the statistician that you are, you decide to do some polling before deciding what issues to run onYou stand by the school library during 4th period and survey every member of your class who walks by What type of survey did you just administer?
Convenience survey
He then draws ten pairs of numbers from a random digit table. The manager will make a surprise visit to the restaurants corresponding to those numbers. Which statement best describes the main flaw in the sampling method for this study?
All the restaurants do not have the same chance of being chosen . The manager is only selecting pairs of numbers from the random digit table . Restaurants with the numbers 100 to 150 have no chance of being chosen.
Which of the following best describes a reason why we may decide to gather data by way of conducting an experiment?
By conducting an experiment, we gain insight into how a specific explanatory variable affects a certain response variable.
A school district has hired a new janitorial services company and the superintendent wants to inspect a random sample of classrooms in each of the district's eight total schools in order to see how well the rooms are being cleaned. Each of the eight schools has its own building The superintendent has decided to conduct a stratified random sample where the eight different school buildings represent eight different strata. In this situation what is an advantage to using stratified random sampling?
By using a stratified random sample, classrooms in every building will be represented in the superintendent's assessment of the performance of the new janitorial services company.
Suppose the superintendent of a large school district is interested in district-wide student satisfaction with the cafeteria food grades K- 12. If the superintendent decided to make a stratified samplewhat could be an effective variable to stratify on?
Favorite food
Data gathering-which of the following statements are true in regards to gathering data?
III only.
Lisa is an artist who makes jewelry from glass beads. She samples each container of beads she receives from the manufacturer to make sure the bead size is consistent with what she ordered Which of the following is the most important for Lisa to include in her sampling in order to ensure that the sample is representative of all of the beads in the container?
Lisa should thoroughly mix the beads in the container and randomly choose the beads for her sample.
What would it mean for this experiment to be double blind? Why is this an important characteristic of the experiment
Neither the individuals who are having their hair shampooed nor the people who are shampooing the hair will know which side of the head is shampooed with which formula. This is important because it helps to reduce the chance that the ratings given by the individuals will be unfairly influenced by knowing which side of their hair received which treatment.
A quality control inspector in a bouncy ball plant must select a simple random sample of bouncy balls at the end of each day to make sure they are producing the required amount of bounciness. Which of the following correctly describes a valid simple random sampling procedure?
Place all of the bouncy balls for the day in a large container and mix them up. Draw 10 bouncy balls out of the container.
A recent study found that people who exercise at least 4 times a week are less likely to have a criminal record than those who do not exercise at all. This fact could be explained by
Some other type of common response or confounding variable.
Which of the following is not a data collection method?
Stratified random sampling.
Jeff sends everyone in his high school a survey asking which of three student council candidates his peers will support. Out of 1,300 students, 403 returned completed surveys. What is the biggest problem with Jeff's survey technique ?
The data may exhibit non-response bias
A personal fitness trainer believes that having his clients participate in counseling groups will improve their success rate in reaching their weight loss goal. To investigate , he conducts an experiment. Which of the following should the personal trainer include in order to conduct a well-designed experiment?
The trainer should include randomization in the experiment by drawing names out of a hat decide which subjects will receive counseling.
Which of the following describes the number of factors and the number of treatments in this study?
There are three factors in 18 treatments.
For each lean customer bank loan officer will If heads the loan officer will promise the applicant a toaster if they complete the application process. it and the toaster will not be offered At the end of the day, the proportion of applicants who completed the loan application for the two groups will be compared Which of the following statements is true ?
This is a completely randomized experiment
Based on the way the sample was designed , what type of sample was used AND what is the biggest problem with using a sample of this type?
This is a convenience sample . When using a convenience sample, it is likely that individuals selected to be part of the sample will not truly represent the population of interest. This means that the results of the survey cannot be generalized to the entire population of students at this high school.
Which of the following best describes the type of sample that Wendy used and the potential concerns that may result from using this type of sample ?
This was a convenience sample consisting only of people that Wendy knows. While these individuals may be easy to reach and will probably be quite cooperative in answering Wendy's questions, the sample may not accurately represent the population of interest.
A study was done to determine whether having a parent who smokes in the house has any effect on whether or not children develop asthma later in life Over a period of several years, the study followed the health records of 140 children whose parent(s) smoked in the house and 140 children whose parent(s) were non-smokers and compared the rates of asthma in these Individuals at the age of 25 Which of the following BEST describes how the study was conducted?
This was a long-term observational study
Suppose a teacher wants to determine whether the 30 students in her learn better by class lecture or by computer program What would be an appropriate matched pairs design to determine this?
Use class rank to pair students together, starting with the two topranked students and pairing through the two lowest-ranked students. Flip a for each pair to determine which student will learn by dass lecture and which will learn by computer program Repeat this process for the remaining pairs. then measure differences in achievement for the 15 pairs.
The 34 students who came to this study session averaged scores 8 points higher on the test than the 72 students who did not come to the study session. Based on this informationwhat may one conclude?
the teacher really wanted to see if the study session is helpful , she should have randomly assigned students to attend the session.
Ms. Jones, an AP Statistics teacher, wonders whether she is giving too much homework. She asks all of her students if the level of homework is a.) about right. b. ) too high . ctoo low. How would one best describe this collection of data?
A census.
In which of the following situations would it be more appropriate to conduct an experiment rather than an observational study?
A developmental psychologist is interested in knowing how different room temperatures affect a preschoolers ability to complete a series of tasks involving fine motor skills.
They surveyed 100 subjects, and gave each of them an unmarked cup of each cola, in randomized order. The researchers found that 56 liked the new cola better. This is an example of
A single-blind experiment
If undercovereage occurs in a sample, it means that
Certain groups of the population were systematically excluded from the sample
The buyer for a cell phone store wants to estimate the proportion of defective cell phones in a shipment of 10, 000 received cell phones. The shipment consists of 500 boxes, each of which contain 20 cell phones The buyer numbers the boxes 1 through 500, and using a random number generator, he selects ten numbers in that range ignoring repeats). He then opens the boxes with the matching numbers and determines the proportion of cell phones that were defective What type of sample is this?
Cluster random sample.
A school nutritionist wants to determine if parents of elementary school children are concerned with the nutritional value of their children's snacksShe decides to conduct an observational study using simple random sampling . Which of the following scenarios best describes this research design?
From a list of all parents of elementary school children in a certain town, 500 parents are selected using a table of random numbers. These parents are then given a choice of two coupon sets: one set is for healthy snacks, and the other set is for unhealthy snacks. The parents can pick only one set of coupons . Their choices are recorded and tabulated
The hemlock woolly adelgid is a small invasive insect that came to North America via Japan and is responsible for killing most of the hemlock trees in the Great Smoky Mountains National Park. To try to control the destruction of hemlock trees caused by the hemlock woolly adelgid, biologists have released lady beetles from Japan (which are known to be natural predators of the hemlock woolly adelgid) onto several of the remaining healthy hemlock trees in the park . Which of the following describes the experimental units in this study?
Healthy hemlock trees in the park
Researchers are curious if there is a connection between childhood cancer rates and living near power lines. What could be a viable way to investigate this relationship? 1. Randomly select 200 children and move half of them near power lines while ensuring the other half de not live near power lines then compare cancer rates. II. Randomly select 100 children who live near power lines and another 100 children who do not live near power lines then investigate cancer rates of the respective groups. III. Randomly select 100 children who have and another 100 children who do not have cancer and compare where the children live.
II and III only
A pollster wants to determine the support of congressional candidate in a certain district. The pollster selects the 12 counties the district represents then randomly selects 10 towns in each of the 12 counties. Finally, he randomly selects 10 subjects in each town for a total of 1,200 respondents in the sample What type of sample best describes this situation?
Multistage sample
A simple random sample of people ages sixty-five and over living in Pinealla County, Florida were surveyed to determine which of the two presidential nominees they favored in the upcoming election To which of the following population can we generalize the survey results to?
Only people 65 and over in Pinella County, Florida
Which of the following is not a feature of a completely randomized experiment?
Sally will divide her friends into two groups - one group of friends who listen to more than five hours of music per week and the other group of friends who listen to less than five hours of music per week. Sally will then randomly assign the two earbud brands to each group of friends.
Which of the following describes the best way to collect the data ?
Send the survey by email to each individual currently enrolled in the customer loyalty program. If an individual does not respond, follow up the email with a paper survey addressed to the individual's home.
In an experiment, a control group is used to
Serve as a baseline to compare effects of one treatment to a standard treatment or placebo
A researcher decided to analyze the weights of smokers and non-smokers. Suppose a random sample of 100 smokers averages 196.4 lbs with a standard deviation of 6.5 lbs, and a random sample of 100 non-smokers averages 174.5 lbs with a standard deviation of 4.6 lbs. What conclusions could be drawn when comparing smokers to non-smokers?
Smokers in this random sample tended to weigh more, but it is unclear if smoking is the reason people weigh more.
A simple random sample of 30 Brand A bulbs and 30 Brand B bulbs are tested by screwing the bulbs into two different sockets at the same time and measuring the average number of hours before the bulbs burn out. What is wrong with this experimental design ?
The type of socket used to test the bulbs is confounding variable.
Despite these scores, why might the professor not be convinced that the course helps?
The variability is such that the higher scores achieved by the group who took the prep course could have been a result of chance.
From this informationthey determined the approximate distance that each student would be traveling to attend college and then calculated the average . What was the goal of gathering this information?
They wanted to be able to estimate the mean distance that all graduating seniors travel in order to attend college .
Which of the following best describes the goal of sample design?
To create a sample that is truly representative of the population of interest.
Hannah's House of Hobbies prints a website address at the bottom of every receipt. Customers can choose to visit the website to answer a customer satisfaction survey. Which type of bias could result from this type of survey?
Voluntary response bias.
If the coin lands on tails, the shopper will be offered a bottle of water and then guided through the showroom by the sales representative. the end of the week, the manager will compare the proportion of shoppers from each group who purchased a pick-up truck that week. What is the response variable in this study?
Whether or not each shopper purchased a truck that week.
A large random sample of people aged 18 to 35 living in the state of Alabama was taken and each individual was surveyed to determine their views on gun control . To which of the following populations might the results of the survey apply?
Only people aged 18 to 35 in the state of Alabama.
Which of the following describes a difference between block design and stratified random sampling?
Block design is a specific method used for designing an experiment while stratified random sampling is a method of gathering a sample .
A researcher for a beverage company would like to test market a new carbonated soft drink. She believes that age might affect the preference for this drink . The researcher divides the population into four age categories and then takes a random sample from each of the age groups . This is an example of..
Stratified sampling
At the end of the growing seasonTerrie compares the number of tomatoes produced from the four sets within each variety group The variable being blocked in this experiment is
The variety of tomato plant
The winner on the show 'So You Think You Can Juggle' is selected based on the number of votes received via text message. At the end of each episode, a text number is displayed on the screen for each of the jugglers. The juggler with the most text votes is the winner of that round of competition This process of selecting each episode's winner suffers from
Voluntary response bias becauspnly those who feel strongly about the jugglers are likely to text their vote
A vice principal wanted to investigate student opinion about a possible change in the high school schedule for the upcoming school year. The vice principal selected random samples of 30 freshmen, 30 sophomores, 30 juniors, and 30 seniors to get their input about the possible change . Which of the following best describes the vice principal's sampling plan ?
A stratified random sample
Even if the lady beetles effectively control the damage done by the hemlock woolly adelgid, it may appear that the lady beetles have no effect on the health and survival rate of hemlock trees in the park. Which of the following may describe why?
All of the above describe possible sources of confounding.
A large hotel has just installed an ice cream bar at its pool and would to gauge its success by conducting a survey The hotel manager randomly selects 3 of the 32 floors of the hotel and surveys all the residents on those 3 floors, The design of this survey is best described as a
Cluster sample.
Can following a vegetarian diet reduce the occurrence of the common cold? An observational study is being planned to compare the average number of colds self -proclaimed vegetarians suffer from each year with the average number of colds non- veg tarians suffer from each year. Which of the following represents the biggest problem with this type of study?
Confounding could occur. Perhaps vegetarians get fewer colds because they try to follow a healthier overall lifestyle than non-vegetarians .
Which of the following statements is true A well-designed survey includes making every possible attempt to reach all of the subjects that were randomly selected to participate A well- designed survey question uses wording that will the answers given by the subjects that the survey will have the results desired by the researchers . A well designed survey uses a random selection of subjects so that its results can be generalized to a larger population
I and III only.
Of the following designs, which would be the best way to use results from their customers to determine the effectiveness of this new detergent
Randomly select 100 current customers, ask them to flip a coin each time they do laundry. If it lands heads they will use the new detergent formula. If it lands tails they will use the old detergent and formula. After 60 days, ask the customers which formula was more effective.
Inarecent poll of students at the local high school, 20\% of the students reported that they did not vote the school should change the lunch menu . However, the vote data showed that actually 55\% of the student body did not vote the school should change the lunch menu. Which of the following types of bias is most to have occurred in the poll?
Response bias.
An engineer has been given the task of adjusting the stop lights at a particular intersection to reduce driver frustration. To begin his study, the engineer needs to randomly select 20 days from the next calendar year to take traffic measurements . Which of the following correctly describes a method for randomly selecting the 20 days?
The engineer will assign each day of the year a unique three digit number from 001 to 365. He will take 20 sets of three digits from a random digit table, ignoring repeats and numbers over 365. The days corresponding to the selected numbers will be in the sample
A large neighborhood association is considering adding a small restroom building to its three neighborhood parks and will choose a random sample of residents to ask their opinions. The association decides to sort the neighborhood homes into two groups: those located near one of the parks and those not located near a park. The association will then randomly choose 10 homes from each of those groups. Which of the following statements is false?
The homeowner's association stratified on the locations of the homes to make the surveys easier to collect
The principal of a large high school would like to gather the opinions of the student body regarding a possible change to how the school schedule would run. He gathers a sample of 100 students by selecting a simple random sample of 25 students from each grade level (freshman, sophomore, junior and senior). What type of sampling method did the principal use and why might he have decided to use this method ?
The principal selected a stratified random sample because he wanted to make sure that opinions from students at each grade level were represented.
What is The essential purpose of blocking, and how does the blocks be designated?
Blocking reduces variability within the blocks, individuals within each block should be as similar as possible.
The offices of a large corporation occupy all floors of a 10-story building. The corporation is planning to renovate the building and would like to incorporate features that will boost the morale af its employees. They will survey a group of 40 employees to help them decide which features to include. The study would be welldesigned with all of the following EXCEPT
Sorting all of the employees into three groups (upper management, middle management and office worker) and randomly choosing one those groups. All of the people in that group will be surveyed
There is not convincing evidence that the study session helps increase scores because
Students who choose to go to the optional study session are most likely more motivated and would have done better regardless of the study session
Which of the following best describes the manner in which data was collected?
Survey
Recent studies have found a strong positive correlation with ice cream sales and boating accidents. This correlation can best be described by the fact that
Temperature is likely a common response variable.
Each laundry load was done with the same detergent, same water temperature, and on the same washing machine. A total of 50 trained observers then felt the towels from each of the three treatment groups for softness. The response variable will be which towel the observers say is the softest. Which of the following could be a problem with this experiment?
The experiment should be single blind so that the observers do not know the brand of softener being used for each towel.
For which of the following populations is 85\% a reasonable estimate of the percentage of those who have been teaching math for more than ten years?
All math teachers who attended the seminar
Ludwig's experiment will NOT be well-designed if it involves
Allowing subjects to select which type of music they listen to during the study period.
While collecting preliminary information from his subjects, the psychologist finds that some work in dimly lit rooms at the end of the day and some work in brightly rooms. Previous studies have shown that brightly lit rooms reduce fatigue On what variable should the experiment be blocked? Why?
The psychologist should block on the lighting in the subjects rooms because he knows that room lighting affects how late a person can stay awake.
