STATS Exam 1
Determine if each of the potential sample survey questions is clear or is slanted towards a desired response. (a) Which of the following best represents your opinion on gun control? 1. The government should take away our guns. 2. We have the right to keep and bear arms (b) In light of skyrocketing gasoline prices, we should consider opening up a very small amount of Alaskan wilderness for oil exploration as a way of reducing our dependence on foreign oil. Do you agree or disagree? (c) Do you think that excessive restrictions placed on U.S. law enforcement agencies hampered their ability to detect the 9/11 terrorist plot before it occurred? (d) Do you use drugs?
(a) clear (b) slanted towards a desired response (c) slanted towards a desired response (d) clear
In a well‑known National Longitudinal Study of Adolescent Health in the mid‑1990s, teenagers responded to survey questions about their health, including their sexual identity and behavior. When the results of this study were analyzed, researchers were surprised that 55 to 77 percent of teenagers were reporting that they identified themselves as homosexual or bisexual, which was an increase from the 11 percent researchers had previously estimated. In general, what could be some challenges in asking teenagers about their sexual identity and behavior?
-The wording of the questions could be important. -Teenagers might not have had the education to express their sexual identities. -Nonresponse could be an issue because teenagers might be reluctant to share personal information
What are the different types of non-sampling errors? Choose all types.
-response error -non response -frame error -processing error
A news reporter states that a study shows that 63% of people prefer vanilla ice cream to chocolate ice cream, plus or minus 2% points. The margin of error in this example is
0.02
You intend to take a random sample of 5 packages from a group of 30 packages of peanuts. You label the packages 01 to 30 and use the line from the table of random digits shown to select the sample. 14459 26056 31424 80371 65103 62253 22490 61181 Using this method you will select the packages of peanuts labeled _____.
14, 03, 10, 22, 06
An experiment is being conducted to determine the optimal fertilizer amount per plant for a particular variety of corn to maximize yield. Corn was planted in small plots randomly assigned to duplicate planting rates of 8,000, 10,000, and 12,000 plants per acre. Fertilizer was applied to each plot at randomized rates that duplicated 100, 150, and 200 pounds per acre. How many explanatory variables are there in this experiment?
2
How many treatments will there be if a researcher wants to design an experiment with two explanatory variables: the intensity of exercise, with two levels, and frequency of exercise, with three levels?
6
An experiment is being conducted to determine the optimal fertilizer amount per plant for a particular variety of corn to maximize yield. Corn was planted in small plots randomly assigned to duplicate planting rates of 8,000, 10,000, and 12,000 plants per acre. Fertilizer was applied to each plot at randomized rates that duplicated 100, 150, and 200 pounds per acre. How many treatments are being used in this experiment?
9
An experiment is being conducted to determine the optimal fertilizer amount per plant for a particular variety of corn to maximize yield. Corn was planted in small plots randomly assigned to duplicate planting rates of 8,000, 10,000, and 12,000 plants per acre. Fertilizer was applied to each plot at randomized rates that duplicated 100, 150, and 200 pounds per acre. If we want to use 10 plots per treatment, how many plots will be needed in this experiment?
90 (There are three levels for planting rate and three levels for fertilizer amount, so these combine to nine treatments for the experiment. For 10 plots per treatment, we'll need 9*10 = 90 plots)
You are writing an opinion poll question about a proposed amendment to the Constitution. You can ask if people are in favor of "changing the Constitution" or "adding to the Constitution" by approving the amendment. One of these choices of wording will produce a much higher percentage in favor. Which one? Why?
A higher percentage of people will prefer adding to the Constitution because many Americans are hesitant about changing the original constitution.
Which of the following statements is true of a census?
A sample can sometimes produce more accurate information than a census.
What is the primary difference between a qualified health claim and an authorized health claim?
An authorized health claim meets the higher standard of significant scientific agreement, while qualified health claims have less scientific support
In a well‑known National Longitudinal Study of Adolescent Health in the mid‑1990s, teenagers responded to survey questions about their health, including their sexual identity and behavior. When the results of this study were analyzed, researchers were surprised that 55 to 77 percent of teenagers were reporting that they identified themselves as homosexual or bisexual, which was an increase from the 11 percent researchers had previously estimated. How can the researchers collect data about sensitive topics in order to get the most accurate results?
Anonymity would not be possible, so identities would have to be protected with sensitive information.
A research physician looked back through patient records and noticed that those patients who were taking anxiety medication had, in general, higher blood pressure than those who did not take the medication. Which of the following is a correct conclusion the physician could draw based on this data?
Anxiety medication is associated with a higher blood pressure
A drug company recruited 500 people into their clinical trial. Half were randomly assigned to take a new experimental weight loss drug for four weeks and the other half were given a placebo. At the end of the four weeks, weight loss for the two groups was compared and there was not a sufficient difference in weight loss between the two groups for the drug to go to market. Which of the following is a true statement regarding this study?
Because there was not a sufficient difference in weight loss between the two groups, whether or not the drug works is still inconclusive.
What is a sampling error?
It is the deviation of the selected sample from the true characteristics or qualities of the entire population.
A research physician looked back through patient records and noticed that those on anxiety medication had, in general, a higher blood pressure. Based on the findings of this study, would it be appropriate for the researchers to state to the public that anxiety medicine causes a higher blood pressure?
No, because observational studies do not allow conclusions about cause and effect and this is an observational study.
A study is being proposed to compare the benefits of jogging versus walking on reducing blood pressure. Sixty adults aged 40 to 55 with high blood pressure are to be divided into groups. Some will be assigned to jog two miles once, twice, or three times a week; others will be assigned to walk three miles once, twice, or three times a week. At the end of three months, the reduction in blood pressure will be compared. What are the treatments in this study?
The six combinations of walking/jogging with frequency once, twice, or three times a week
You are writing an opinion poll question about a proposed amendment to the Constitution. You can ask if people are in favor of "changing the Constitution" or "adding to the Constitution" by approving the amendment. Why may the responses to these two questions produce different percentages in favor?
The words "changing" and "adding" have different connotations.
In a well‑known National Longitudinal Study of Adolescent Health in the mid‑1990s, teenagers responded to survey questions about their health, including their sexual identity and behavior. When the results of this study were analyzed, researchers were surprised that 55 to 77 percent of teenagers were reporting that they identified themselves as homosexual or bisexual, which was an increase from the 11 percent researchers had previously estimated. How would you get a nationally representative sample of U.S. teenagers?
Use cluster sampling. Divide the country by geographic area and randomly select some of the areas. Within each selected area, obtain a simple random sample (SRS) of schools in that area. Then survey all students in each selected school. Stratify within each cluster if appropriate. Random samples or stratified random samples would be the most representative but difficult to obtain because you would need the names of all teenagers in order to form the sample.
Airport administrators take a sample of airline baggage and record the number of bags that weigh more than 75 pounds. What is the variable of interest?
Whether the bag weighs more than 75 pounds
In a study of commuting patterns of people in a large metropolitan area, respondents were asked to report the time they took to travel to their work on a specific day of the week. What is the individual in this description?
a person
A professor wants to determine the average age of all students enrolled in statistics courses at State University. She obtains data from 167 currently enrolled students. In this context, the variable of interest would be _____.
age
What we eat can have an effect on our health and weight. A new study reported in the New England Journal of Medicine found that, based on following 120,877 health professionals over a 20-year period, adults' food choices contributed nearly four pounds of extra weight every four years. (source: Alicia Chang, "Which snack food is making you fat?" (original source: Dariush Mozaffarian, M.D., Dr.P.H et al, "Changes in Diet and Lifestyle and Long-Term Weight Gain in Men and Women," New England Journal of Medicine, 364:2392-2404, June 23, 2011.))
all adults
People were asked whether they had pretended to use a cell phone to avoid talking with someone in an awkward situation. What type of study is this?
an observation study
Young men aged 14 to 22 were asked about their tanning habits. Specifically, they were asked whether they tanned, and if so, whether they tanned using a tanning bed or tanned with natural sunlight or both. They were also asked about the frequency of their tanning. What type of study is this?
an observational study
Studies completed using simple random samples are likely to be trusted because the randomness _____.
avoids bias
In an experiment, treatments are chosen for each subject _____.
based on random assignment
A voluntary response sample is a sampling method that generally leads to _____.
bias
Allowing subjects to select their treatments will likely result in _____
bias
"Ann Landers" is famous for giving advice. Once, in response to a letter from an engaged couple, she asked her readers to write and respond to the question "If you could do it over again, would you have children?" She received over 10,000 responses, 70% of whom said they would not have had children if they could do it over again. These results cannot be generalized to the entire population of parents due to voluntary response, making this a _____ study.
biased
Results of an experiment may be _____ if all individuals are not treated exactly the same except for the application of the actual treatments.
biased
Using a placebo helps researchers _____ subjects as to which treatment they receive.
blind
What is the name of the group of individuals that are similar in some way that affects the response variable?
block
A census is a sample survey that attempts to include the entire _____ in the sample.
categorical
Students at a university can choose to register for section 001, 002, 003, 004, or 005 of a certain statistics course. "Section" is considered a _____ variable.
categorical
A university wants to gauge student opinion about the creation of a new building. To do this, they contact every student in the university and ask their opinions on the new building. This study is an example of a(n)
census
Robert is interested in testing the efficacy of a new drug on breast cancer. He finds 20 women with breast cancer to agree to receive the treatment and who also know that they may receive a placebo instead. He randomly assigns the patients to either the placebo group or the treatment group. This is an example of a ___________ trial because there is an experimental group and a control group.
clinical
An Austrian study investigated whether keeping a surgery patient's body temperature close to normal by heating the patient during surgery decreases wound infection rates. Patients undergoing colon or rectal surgery were randomly assigned to one of two treatment groups. In the normal-thermic group, patients' core temperatures were maintained near 36.5 degrees Celsius. In the hypothermic group, patients' core temperatures were allowed to decrease to about 34.5 degrees Celsius. (Data from EESEE.) What type of study is this?
completely randomized experiment
A university is performing an experiment to see if sleep deprivation has an effect on test performance. They tell patients that they will then share each patient's personal results with the rest of the participants. This is violating the ethical principle of _____________.
confidentiality
The principle of ethical studies that is always necessary in behavioral experiments is _____.
confidentiality
A recent medical study found that people who drink more than four cups of coffee a day have more heart attacks than people who drink less coffee or no coffee. This led some doctors to suspect that coffee may be a contributing factor in causing heart attacks. However, more careful analysis of the data showed that heavy coffee drinkers tend to smoke more than other people. This is an example of
confounding
The main purpose of the U.S. census is to _____.
create election districts with equal populations
If you consent to a behavioral or social science experiment, you could actually be misled about the study or the intent of the study because _____ is allowed.
deception
When experiments are not fully realistic, they are _____ to generalize into a bigger population
difficult
Airport administrators take a sample of airline baggage and record the number of bags that weigh more than 75 pounds. What is the individual?
each piece of baggage
Clinical trials are experiments that study the _____ of medical treatments on actual patients.
effectiveness
In a well‑known National Longitudinal Study of Adolescent Health in the mid‑1990s, teenagers responded to survey questions about their health, including their sexual identity and behavior. When the results of this study were analyzed, researchers were surprised that 55 to 77 percent of teenagers were reporting that they identified themselves as homosexual or bisexual, which was an increase from the 11 percent researchers had previously estimated. How would you collect data about sexual behavior and identity to get the most accurate answers?
ensure responses are annoymous
A(n) _____ can be used to establish a cause and effect relationship between the explanatory and response variables.
experiment
In a(n)_____ researchers impose treatments on individuals in order to see how they respond.
experiment
Participants in a fitness study were randomly assigned to jog on a treadmill 3 times a week for 30 minutes, jog a course 3 times a week for 30 minutes, or do no jogging. Resting heart rate was measured after a month and the joggers had a lower average resting heart rate compared to the non-joggers. This study is an example of a(n) _____.
experiment
The researcher randomly assigns the treatments to individuals in an experiment to observe their effects.
experiment
Researchers counted the number of boats using a public boat landing each day of the past year. This is an example of a(n) _____ study.
experimental
Researchers want to see if an athlete's diet affects his speed. Thirty participants are given either a carbohydrate loaded diet or a protein loaded diet and their speeds on a 100 meter dash are recorded. This study is an example of a(n) _____ study.
experimental
Institutional review boards (IRBs) are tasked with reviewing all studies involving _____ subjects to protect their rights and welfare.
human
informed consent means subjects must be informed _____ about the study.
in advance
What is the best way to control random sampling error?
increase sample size
The three basic requirements of an ethical experiment are: the presence of an institutional review board, subject confidentiality, and ______________consent.
informed
One principle of ethical studies that is not always necessary in behavioral experiments is _____________.
informed consent
The _____ review board reviews all planned studies to protect the subjects from possible harm.
institutional
For two types of groups with systematic differences in the response variable, a completely randomized design gives _____ precise results compared to randomized block design
less
In a pre-election poll, surveyors are usually most interested in the opinions of _____.
likely voters
A university professor wanted to know if her students' attitudes towards statistics change during the course of the semester. She takes a simple random sample of students and gives them a test at the beginning of the term to assess their feelings toward statistics. When the semester is finished, she administers another test to the same group of students to see if there is a difference in attitude. This experiment uses a _____.
matched pair designs
Institutional review boards (IRBs) are tasked with reviewing all studies involving human subjects to protect their rights and welfare. One criticism of the IRB process is that when they are overworked they may be tempted to categorize some studies as __________ when they shouldn't be.
minimal risk
The APA allows deception if it is _____ to the study.
necessary
In an experiment to test the effects of a drug on quality of sleep, 30 individuals who have trouble sleeping were randomly assigned to either receive the drug or a placebo. However, many individuals participating in the study did not take their medication as directed. The type of bias present here is a result of _____.
nonadherence
The New York Times places a poll on page five asking readers to respond on their opinion of the President. This sample should _____.
not be trusted because this sample is voluntary response
A study uses a sample taken from the 8 am classes on campus on Monday morning to poll the student body on campus safety. You should _____.
not trust this study because the sample is convenience
A sample survey is classified as a(n) _____ study.
observational
You study the study habits of 30 classmates in order to see if the amount of time spent studying relates to test performance. This is an example of a(n) _____ study.
observational
Researchers counted the number of boats using a public boat landing each day of the past year. This is an example of a(n) _____.
observational study
The goal of a(n) _____ is to observe without interfering.
observational study
Unlike completely randomized designs, treatments are randomly assigned to subjects within each _____ in a matched pairs design
pair
A consequence of not using a(n) _____ in the control group is that subjects may not be blinded as to whether they receive the active treatment.
placebo
A good sample is representative of the _____.
population
In a pre-election poll, the real _____ of interest is likely voters.
population
Many sports teams want to have strong, fast players. In one league, no player has ever run the 40 yard dash in less than 4.2 seconds. In measuring the league's fastest time, we can assume that the 4.2 seconds threshold is most likely based on data obtained from the _____.
population
Many sports teams want to have strong, fast players. In one league, no player has ever run the 40 yard dash in less than 4.2 seconds. In measuring the league's fastest times, we could consider the 4.2 seconds threshold is most likely based on data obtained from the _____. (Your answer should be one word.)
population
n a pre-election poll, the real _____ of interest is likely voters.
population
A famous quote from the Declaration of Helsinki states the "interest of the subjects must always _____".
prevail
It would be against basic data ethics principles to _________
publish an individual's results from a study
A study is being proposed to compare the benefits of jogging versus walking on reducing blood pressure. Sixty adults aged 40 to 55 with high blood pressure are to be divided into groups. Some will be assigned to jog two miles once, twice, or three times a week; others will be assigned to walk three miles once, twice, or three times a week. If half the subjects are men and half women, what would be a good experimental design?
randomize the women and men separately to all treatments
Just like completely _____ designs, matched pairs designs incorporate randomization and control/comparison.
randomized
A study to investigate a new potential treatment for Alzheimer's disease used a special insulin nasal spray to get sugar to the brain in less than 30 minutes' time. The 104 volunteers who participated in the study either had Alzheimer's or pre-Alzheimer's memory problems. Those with Alzheimer's were randomly assigned to either receive a daily dose of insulin or to receive a placebo. Those with pre-Alzheimer's were also randomly assigned to the two treatments. What type of study is this?
randomized block experiment
In a randomized block design, randomization is not necessary since all individuals in the block should be the similar in some respects that affect the _____ variable
response
In a well‑known National Longitudinal Study of Adolescent Health in the mid‑1990s, teenagers responded to survey questions about their health, including their sexual identity and behavior. When the results of this study were analyzed, researchers were surprised that 55 to 77 percent of teenagers were reporting that they identified themselves as homosexual or bisexual, which was an increase from the 11 percent researchers had previously estimated. What type of error is it when a subject does not answer a question seriously?
response error
In a well‑known National Longitudinal Study of Adolescent Health in the mid‑1990s, teenagers responded to survey questions about their health, including their sexual identity and behavior. When the results of this study were analyzed, researchers were surprised that 55 to 77 percent of teenagers were reporting that they identified themselves as homosexual or bisexual, which was an increase from the 11 percent researchers had previously estimated. What type of error is it when the survey question is worded in a confusing way?
response error
What we eat can have an effect on our health and weight. A new study reported in the New England Journal of Medicine found that, based on following 120,877 health professionals over a 20-year period, adults' food choices contributed nearly four pounds of extra weight every four years. (original source: Dariush Mozaffarian, M.D., Dr.P.H et al, "Changes in Diet and Lifestyle and Long-Term Weight Gain in Men and Women," New England Journal of Medicine, 364:2392-2404, June 23, 2011.) In this study, the 120,877 health professionals are the _____.
sample
Classify each error as a sampling error or a non-sampling error. sampling error -the mean in the sample is not equal to the mean of the population -sometimes there are more people in the park than other times -a mistake is made while entering data -the person distributing the medicine subconsciously made a face when handing out the placebo pill -a group of people was accidentally underrepresented in the sample -the way questions were worded influences the responses -some people refused to answer certain questions, and these people are likely to have different opinions than those who did answer those questions
sampling error: -the mean in the sample is not equal to the mean of the population -sometimes there are more people in the park than other times non-sampling error: -a mistake is made while entering data -the person distributing the medicine subconsciously made a face when handing out the placebo pill -a group of people was accidentally underrepresented in the sample -the way questions were worded influences the responses -some people refused to answer certain questions, and these people are likely to have different opinions than those who did answer those questions
A treadmill company is conducting a study to determine if running on the treadmill 30 minutes per day at lunch will help with cardiovascular health. One hundred employees of an investment firm in a posh high rise were chosen for the study. At the end of three months, their cardiovascular health was evaluated and found to be significantly improved. The results of this study cannot be generalized to all people because _____.
the 100 employees of an investment firm in a posh high rise are not representative of all people
Researchers from the Smell and Taste Treatment and Research Foundation tested the hypothesis that the presence of floral scent can improve a person's learning ability. For the test, they studied the time required for 21 adults mostly in their 20's and 30's to complete two sets of mazes. Each subject completed one set of mazes while wearing a floral scented mask and the other set while wearing an unscented mask. The order was randomized. Use of a matched pair design is used here to minimize variation due to _____.
the ability of each individuals to solve mazes
Which of the following is the best description of the individuals within a block in a block design?
the individuals are similar with respect to the characteristic of interest that defines the block
"American Idol," "Dancing with the Stars" and other reality programs often make statements such as "more people voted in the finals than voted for the President in the last election." That means ______________.
the winner is the one who convinced the most people to cast votes for him or her.
Some ethical difficulties may exist in medical treatments because _____.
they could do good or harm to the subject
In a study of commuting patterns of people in a large metropolitan area, respondents were asked to report the time they took to travel to their work on a specific day of the week. What is the variable of interest?
travel time
A main purpose of doing an experiment over an observational study is to learn whether a certain _____ causes a certain response.
treatment
You weigh yourself five times on a scale. The measurements are 155, 156, 152, 154, and 155. Your true weight is 155 lbs. The error present here is _____.
variability
In observational studies, _____ are measured.
variables
In 2010 a poll on a website for Democratic supporters asked "Do you think President Obama has helped the economy?" 82% of the respondents said "yes". This sample is a(n) _____ response sample.
voluntary
The American Psychological Association requires consent from subjects to participate in experiments except _________.
when the behavior is observed in a public place