Exam review STAT 303
Medical researchers know that the probability of getting lung cancer if a person smokes is 0.34. The probability that a nonsmoker will get lung cancer is 0.03. It is also known that 11% of the population smokes. What is the probability that a randomly selected person is both a smoker and gets lung cancer? A) 0.0374 B) 0.3240 C) 0.3400
A) 0.0374
Rhinos are either black or white. 82% of the world's rhinos are African. 33% of African rhinos are black, 67% of African rhinos are white. What is the probability that a randomly chosen rhino would be a black African rhino? A) 0.27 B) 0.33 C) 0.40 D) 0.82
A) 0.27
For two events A and B, P(A) = 0.4 and P(B) = 0.5. Then P(A or B) equals A) 0.7, if A and B are independent. B) 0.7, if A and B are disjoint.. C) 0.2, if A and B are independent. D) 0, if A and B are disjoint. E) 0.9, if A and B are independent
A) 0.7, if A and B are independent.
Without using a calculator. Choose one of the data sets below that has the smallest possible standard deviation. (Hint: standard deviation measures the average deviation between data values and the mean) A) 10, 10, 10, 10 B) 0, 0, 1, 1 C) 7, 8, 9, 10 D) 0, 0, 10, 10
A) 10, 10, 10, 10
A data set contains the nutritional content per serving of 77 brands of breakfast cereal. Manufacturer, cold/hot, calories, grams of sugar, and grams of fiber are recorded for each cereal brand. Identify the individual/subject in this data set. A) 77 brands of cereal B) manufacturer C) number of calories D) grams of sugar and fiber
A) 77 brands of cereal
An education researcher randomly selects 38 schools from one school district and interviews all the teachers at each of the 38 schools. Identify the type of sampling used in this example. A) Cluster sampling B) Attempted census C) Stratified sampling D) Simple random sampling E) Voluntary response sampling
A) Cluster sampling
A social scientist is interested in studying the drinking habits of college students. She randomly picks 1,000 students from the college directory using an automated computer system. What aspect of statistics has she just completed? A) Design B) Description C) Inference
A) Design
What is the correct format of a data file? A) Each row represents a subject in the study and each column represents a characteristic about that subject. B) Each row represents a characteristic about a subject and each column represents a subject.
A) Each row represents a subject in the study and each column represents a characteristic about that subject.
A personal trainer decides to track the amount of time each of her clients spends exercising and their amount of weight loss in a two month period. What are the explanatory and response variables? A) Explanatory variable: time spent exercising Response variable: weight loss B) Explanatory variable: weight loss Response variable: time spent exercising C) Cannot be determined
A) Explanatory variable: time spent exercising Response variable: weight loss
Researchers reported that for men, being unmarried increases the risk of depression. These findings were based on the medical records of 400 married men and 500 unmarried men. This conclusion is not justified because there may be lurking variables. Which of the following are possible lurking variables? I: Depression II: Income III: Type of employment IV: Age V: Gender A) II, III, IV B) II, IV C) III, IV D) II, III
A) II, III, IV
The General Social Survey (GSS) asks questions to a sample of Americans to determine their opinions about a wide range of topics every other year. In 2006 the GSS survey asked 2,815 participants if they were in favor or opposed to the death penalty for those convicted of murder. What is the sample? A) The 2,815 participants B) All adults in the United States C) All adults in the world
A) The 2,815 participants
Identify the answer choice that is an example of a discrete quantitative variable. A) The number of people to complete a 5K run. B) The time to complete a 5K run. C) The weight of each participant in a 5K run. D) The amount of each participants exertion (high, medium, low) in a 5K run. E) The types of running shoes worn in a 5K run.
A) The number of people to complete a 5K run.
Which graphic would best display the distribution of the top ten causes of death in the United States? A) bar graph B) time plot C) histogram D) stem-and-leave plot
A) bar graph
A news release from a diet product company reports: "There is good news for the 65 million Americans currently on a diet." Its study showed that people who lose weight can keep it off. The sample was 20 graduates of the company's program who endorse it in commercials. The results of the sample are probably: A) biased, overstating the effectiveness of the diet. B) biased, understating the effectiveness of the diet. C) unbiased because these are nationally recognized individuals. D) unbiased, but they could be more accurate. A larger sample should be used.
A) biased, overstating the effectiveness of the diet.
We asked people to classify their weight as underweight, normal, overweight, or obese. Would this variable be a categorical or quantitative variable? A) categorical B) quantitative
A) categorical
An experimental design randomly assigns volunteer arthritis sufferers to take either a new pain medication, aspirin, or a placebo. An institutional review board discusses whether the experiment should include a placebo. This is an: A) ethical issue. B) issue of lack of replication. C) issue of lack of realism.
A) ethical issue.
Consider the event that one child in New York gets the flu and a second event in which a second child in Los Angles gets the flu. These two events are most likely: A) independent B) dependent
A) independent
A hidden variable that stands behind a relationship and determines it by simultaneously affecting the other two variables is called a ______ variable. A) lurking B) causal C) response D) predictor
A) lurking
The Current Population Survey conducted every month by the Bureau of Labor Statistics would be considered: A) observational. B) experimental.
A) observational.
A study surveyed from 1986 to 2000 a large number of male health professionals aged 40 to 75. Each respondent filled out a lifestyle questionnaire every two years. The 22,086 subjects who had reported having good erectile function in 1986 were included in an analysis of risk factors in the development of ED. The analysis revealed that "obesity and smoking were positively associated and physical activity was inversely associated with the risk of ED developing." This is a(n): A) prospective observational study. B) retrospective observational study. C) experiment.
A) prospective observational study.
The ______ is the outcome variable on which comparisons are made. A) response variable B) explanatory variable C) predictor variable D) both B and C
A) response variable
An experiment that tests a new treatment for earlystage HIV is tested against an already accepted treatment. Fifty early-stage HIV patients are placed in each group. Of the 50 given the new treatment, 40 show improvement within the first month. Of the 50 given the accepted treatment, 35 show improvement within the first month. The sample consists of: A) the 100 patients treated. B) the 75 patients who showed improvement. C) all HIV patients. D) all HIV patients with early-stage HIV
A) the 100 patients treated.
In 1981, 22,071 physicians with no history of heart incidents were randomly assigned to receive active aspirin and active beta-carotene, active aspirin and betacarotene placebo, aspirin placebo and active betacarotene, or aspirin placebo and beta-carotene placebo. The occurrence of heart incidents were recorded through 1989. Identify the subjects in this experiment. A) the 22,071 physicians B) the occurrence or non-occurrence of heart incidents C) the presence or absence of aspirin and betacarotene
A) the 22,071 physicians
In a survey of women who were asked to name their favorite color, 17% said blue, 18% said red, 18% said green, 14% said yellow, and 11% said black. If you pick a survey participant at random, what is the probability that her favorite color is not red? A) 0.72 B) 0.82 C) 0.18 D) 0.60
B) 0.82
In an experiment on a new drug, subjects were randomly assigned to either a placebo or the active drug. In addition, the method of delivery of the drug (pill, skin patch, or nasal mist) was considered. How many factors were there in this experiment? A) 1 B) 2 C) 3 D) 6
B) 2
In 1981, 22,071 physicians with no history of heart incidents were randomly assigned to receive active aspirin and active beta-carotene, active aspirin and betacarotene placebo, aspirin placebo and active betacarotene, or aspirin placebo and beta-carotene placebo. The occurrence of heart incidents were recorded through 1989. How many treatment groups are in this experiment? A) 2 B) 4 C) 6 D) 8
B) 4
A fair coin has come up "heads" 10 times in a row. The probability that the coin will come up heads on the next flip is A) less than 50%, since "tails" are due to come up. B) 50%. C) greater than 50%, since it appears that we are in a streak of "heads." D) It cannot be determined.
B) 50%.
A social scientist is interested in studying the drinking habits of college students. She randomly picks 1,000 students from the University of Florida phone directory using an automated computer system. What is the population? A) The 1,000 students sampled B) All students at the University of Florida C) All students in universities across the U.S.
B) All students at the University of Florida
Scientists are interested in the health of yellow fin snapper in the Bahamas. In the Bahamas, twenty yellow fin snapper are captured, weighed, have a blood sample taken and then are released. The average weight of the 20 snappers was 2.5 pounds. What is the population? A) Twenty yellow fin snapper B) All yellow fin snapper in the Bahamas C) All yellow fin snapper in the world D) 2.5 pounds
B) All yellow fin snapper in the Bahamas
At the end of each semester a local university requires a professor's evaluation. An evaluation survey is given to each student to fill out. Identify the type of sampling used in this example. A) Cluster sampling B) Attempted census C) Stratified sampling D) Simple random sampling
B) Attempted census
Is there a link between prostate cancer and heating meals in plastic containers in the microwave? Suppose 300 people with prostate cancer and 300 people of a similar age but without prostate cancer were asked if they heated food in the microwave in a plastic container. What type of observational study is this? A) Cross Sectional B) Case-Control C) Prospective
B) Case-Control
A social scientist is interested in studying the drinking habits of college students. She asks each student how many drinks they had last Saturday night. She finds the average for 1,000 randomly selected students and creates a graph to display the results. What aspect of statistics is described in bold type? A) Design B) Description C) Inference
B) Description
True or False: If a statistic is listed in the newspaper it can be trusted completely. A) True, newspapers only print reliable information. B) False, not all data in the newspaper comes from reliable studies.
B) False, not all data in the newspaper comes from reliable studies.
True or False: If a data set is listed on the internet it can be trusted. A) True, if it is posted on the internet it must be a source of reliable data. B) False, not all data on the internet is reliable, check the source of the data.
B) False, not all data on the internet is reliable, check the source of the data
True or False: The opinion polls that can be completed on news websites such as cnn.com are good ways to determine the American public's opinions about popular topics. A) True, it is a well respected news site so the results of its surveys can be trusted. B) False, the people who complete these surveys do not constitute a representative sample of Americans.
B) False, the people who complete these surveys do not constitute a representative sample of Americans.
Suppose that two researchers both randomly sampled 400 different students at the University of Miami and asked the students if they consumed any alcoholic beverages in the past week. From their sample, the researchers each computed the proportion of students that consumed an alcoholic beverage in the past week. Are the two proportions from the two samples the same? A) Yes, both researchers drew from the same population. B) Probably not, samples vary.
B) Probably not, samples vary.
Suppose that a medical test has a 92% chance of detecting a disease if the person has it and a 94% chance of correctly indicating that the disease is absent if the person really does not have the disease. Which statement is true about the medical test? A) The sensitivity is 94% and the specificity is 92% B) The sensitivity is 92% and the specificity is 94% C) The accuracy rate of the test is 92% D) The accuracy rate of the test is 93%
B) The sensitivity is 92% and the specificity is 94%
Does gastric freezing reduce ulcer pain? A group of subjects (ulcer patients) were exposed to a treatment (gastric freezing) and the outcome (pain reduction) was observed. Which statement is true? A) This was a controlled experiment which would help determine the effectiveness of gastric freezing. B) This was an uncontrolled experiment in that there were lurking variables and a placebo effect taking place.
B) This was an uncontrolled experiment in that there were lurking variables and a placebo effect taking place.
In a pollution study water samples from 100 different locations in Lake Champlain were taken and the level of nitrates was measured. What is the individual/subject? A) Lake Champlain B) a given location in Lake Champlain C) the level of nitrates measured D) the scientist conducting the study
B) a given location in Lake Champlain
You can summarize the data for two categorical variables by A) drawing a scatterplot B) constructing a contingency table C) constructing a box plot for each variable. D) constructing a side-by-side box plot.
B) constructing a contingency table
When a biologists takes a sample from one location in a lake rather than sampling various locations in the lake, he/she is probably doing: A) voluntary sampling. B) convenience sampling. C) random sampling. D) population sampling.
B) convenience sampling.
Consider the event that one child in a class gets the flu and a second event in which a second child in the same class gets the flu. These two events are most likely: A) independent B) dependent
B) dependent
A sample of two light bulbs is selected in succession, without replacement, from among 6 good ones and 4 defective ones. What is the complement of the event "at least one light bulb is defective"? A) at least one bulb is not defective B) neither bulb is defective C) both bulbs are defective
B) neither bulb is defective
Is the right foot more powerful than the left? A researcher decides to measure foot power by having subjects kick a large Styrofoam block and measure the depth of the impression. Twenty subjects are available for the experiment. What would be an important element of randomization in this experiment? A) order in which subjects are tested B) order in which subjects kick (right/left) C) gender of subjects D) weight of subjects
B) order in which subjects kick (right/left)
The Current Population Survey (CPS) is conducted by the Bureau of Labor Statistics each month in which they survey 60,000 U.S. households. If 35,000 households reply to the survey, identify the sample in this survey. A) the 60,000 surveyed households B) the 35,000 households that replied to the survey C) all U.S. households D) all U.S. citizens
B) the 35,000 households that replied to the survey
A psychologist wants to know if adults with normal vision can be fooled by a certain optical illusion. She recruits 50 students with normal vision from her class and finds that 42 of them are fooled by the illusion. The sample was: A) the 42 students who were fooled. B) the 50 students who served as subjects. C) all students in the class. D) all adults with normal vision.
B) the 50 students who served as subjects.
In order to avoid unconscious bias, neither the subjects nor the doctors who examined them knew whether a particular subject was taking vitamins or dummy pills. This is called: A) the placebo effect. B) the double-blind technique. C) internal validity. D) the retrospective method.
B) the double-blind technique.
Medical researchers at a large city hospital investigating the impact of prenatal care on newborn health collected data from 882 births during 1998-2000. They kept track of the mother's age and the number of weeks the pregnancy lasted. Which variable should be plotted on the horizontal axis? A) the mother's age because it is the response variable B) the mother's age because it is the explanatory variable C) the number of weeks that the pregnancy lasted because it is the response variable D) the number of weeks that the pregnancy lasted because it is the explanatory variable
B) the mother's age because it is the explanatory variable
The Public Health Service and the Tuskegee Institute began a study on syphilis in 1932. Nearly 400 poor Black men with syphilis from Macon County, Alabama, were enrolled in the study. They were never told that they had syphilis and were never told of any possible risks to them. This was a clear violation of which ethical principle? A) the formation of an institutional review board B) the obtaining of informed consent C) keeping individual data confidential
B) the obtaining of informed consent
A health survey was conducted among households in a community that were selected at random from the telephone directory. In this community, 4% of households have no telephone and another 35% have unlisted telephone numbers. The sample will likely suffer from (select the best answer) A) nonresponse. B) undercoverage. C) false responses.
B) undercoverage.
Suppose a medical test has a 95% sensitivity and 90% specificity. If 5% of the population have the condition for which the test is being used, what is the probability that a randomly selected person will not have the condition and will test positive (i.e. false positive)? A) 0.0025 B) 0.0475 C) 0.095 D) 0.855
C) 0.095
Medical researchers know that the probability of getting lung cancer if a person smokes is 0.34. The probability that a nonsmoker will get lung cancer is 0.03. It is also known that 11% of the population smokes. What is the probability that a nonsmoker does not get cancer? A) 0.03 B) 0.92 C) 0.97
C) 0.97
Identify the list which contains only quantitative variables. A) Favorite food, height, SAT score B) Weight, zip code, height C) GPA, height, SAT score D) Time to run 15K, SAT score, HIV status e) Time to run 15K, major in school, zip code
C) GPA, height, SAT score
Without using a calculator. Choose (if any) data sets below that have the same standard deviation. I. 10, 10, 10, 10 II. 0, 0, 1, 1 III. 7, 8, 9, 10 IV. 0, 1, 2, 3 A) I and II B) II and IV C) III and IV D) None
C) III and IV
Identify the list which contains only categorical variables? A) Month of birth, age, favorite color B) Month of birth, height, weight C) Marital status, major in school, HIV status D) Marital status, height, favorite color e) HIV status, marital status, GPA
C) Marital status, major in school, HIV status
Which measure of center is most influenced by outliers? A) Mode B) Median C) Mean D) Standard deviation E) Variance
C) Mean
In 2006 the GSS survey asked 2,815 participants if they were in favor or opposed to the death penalty for those convicted of murder and 67% of those surveyed stated that they were in favor of the death penalty. What is the parameter and the statistic? A) Parameter = 67% Statistic = 67% B) Parameter = 67% Statistic = unknown C) Parameter = unknown Statistic = 67% D) Parameter = unknown Statistic = unknown
C) Parameter = unknown Statistic = 67%
A survey question asked: "Which of the following best describes your dinner on weekends?" Fast food from the drive-through, which we eat in front of the TV. A sit-down meal at our favorite family restaurant. A quick meal prepared that night and eaten at the dining room table. Microwaved leftovers To summarize the results of this question from all respondents, which statistics should be used? A) Means B) Medians C) Proportions D) Modes
C) Proportions
More dogs are being diagnosed with thyroid problems than have been diagnosed in the past. A researcher identified 50 puppies not already diagnosed with a thyroid problem and followed the dogs for several years to see if any developed thyroid problems. This is a(n) A) Randomized experiment B) Survey C) Prospective study D) Retrospective study
C) Prospective study
Autism is a disorder of neural development characterized by impaired social interaction and communication, and by restricted and repetitive behavior. About 1 in 1000 children are born with autism. In order to compare children born with autism to those not born with autism, one would use: A) a simple random sample of children. B) a retrospective study. C) a case-control study. D) a cohort study.
C) a case-control study.
One hundred volunteers who suffer from depression are available for a study involving a new drug that is thought to be effective in treating depression. The researchers want to compare the new drug to the drug currently in use. It is believed that men and women may respond differently to the drugs. Which of the following would be the most appropriate design for this experiment? A) a matched pairs design B) a completely randomized design C) a completely randomized block design
C) a completely randomized block design
A subject who suffers from bronchial asthma reported an alleviation of symptoms after taking an inert substance, distilled water. The subject was displaying: A) a confounded response B) a randomized response C) a placebo response D) a statistically significant response
C) a placebo response
A recent study demonstrated that 25% of American women are red/green color blind. This can be interpreted as meaning: A) in a group of 100 American women, 25 will be color blind. B) one out of every four American women will be color blind. C) a randomly chosen American woman has a 25% chance of being color blind.
C) a randomly chosen American woman has a 25% chance of being color blind.
Respondents to a lifestyle survey may not truthfully answer a question on the use of illegal drugs. This is an example of: A) a nonresponse. B) under coverage. C) a response error. D) a processing error.
C) a response error.
The Current Population Survey (CPS) is conducted by the Bureau of Labor Statistics each month in which they survey 60,000 U.S. households. If 35,000 households reply to the survey, identify the implied population in this survey. A) the 60,000 surveyed households B) the 35,000 households that replied to the survey C) all U.S. households D) all U.S. citizens
C) all U.S. households
A statistical study that systematically favors certain outcomes is said to be: A) confounded. B) a simple random sample. C) biased. D) voluntary.
C) biased.
A treatment for early-stage HIV is being compared to an already accepted treatment. If this experiment uses the double-blind technique: A) the person administering the treatment knows whether the subject is getting the new treatment or not, but the subject does not know. B) the subject knows whether he/she is getting the new treatment, but the administering person does not know. C) both the administering person and subject do not know whether the subject is getting the new treatment.
C) both the administering person and subject do not know whether the subject is getting the new treatment.
An event A will occur with probability 0.5. An event B will occur with probability 0.6. The probability that both A and B will occur is 0.1. We may conclude that A) events A and B are independent. B) events A and B are disjoint. C) events A and B are neither independent nor disjoint D) None of the above
C) events A and B are neither independent nor disjoint
An example of a non-sampling error that can reduce the accuracy of a sample survey is: A) Using voluntary response to choose the sample. B) interviewing people at a shopping mall to obtain a sample. C) having a low rate of return after mailing surveys to participants' homes.
C) having a low rate of return after mailing surveys to participants' homes.
Voluntary response polls almost always suffer from: A) the placebo effect. B) highly variable results. C) high bias. D) randomization.
C) high bias.
A researcher wants to show the distribution of times it took subjects who smoke to fall asleep. Which graphic would be the best choice? A) bar graph B) time plot C) histogram D) pie chart
C) histogram
Is the right foot more powerful than the left? A researcher decides to measure foot power by having subjects kick a large Styrofoam block and measure the depth of the impression. Twenty subjects are available for the experiment. What would be the best design for this experiment? A) randomized block design B) double-blind design C) matched pairs design D) completely randomized design
C) matched pairs design
Which value cannot be read from a boxplot? A) minimum B) first quartile C) mode D) median
C) mode
The basic principles of experimental design include: A) randomization, number of subjects, and use of double-blind procedures. B) control, use of at least single-blind procedures, and randomization. C) randomization, use of enough subjects, and control.
C) randomization, use of enough subjects, and control.
Fish taken from a lake in upstate New York are divided by species before being measured. This is an example of: A) simple random sampling. B) multistage sampling. C) stratified sampling. D) voluntary sampling.
C) stratified sampling.
Researchers studied 29,000 Finnish men, all smokers over the age of 50. Half of the men, selected at random, took vitamin supplements, and the other half took a dummy pill that has no active ingredient. The researchers followed all the men for eight years. At the end of the study, men in the vitamin group were no less likely to have cancer than men in the other group. Identify the control group. A) the 29,000 Finnish men B) the 14,500 Finnish men who took vitamin supplements C) the 14,500 Finnish men who took a dummy pill
C) the 14,500 Finnish men who took a dummy pill
Which of the following measures is not affected by the presence of outliers? A) the mean B) the standard deviation C) the IQR
C) the IQR
An experiment comparing three drug types―A, B, and C―is performed. A group of subjects is divided into three groups by age: 20-40, 41-60, and 61+. The 20- to 40-year-olds receive drug A, the 41- to 60-year olds receive drug B, and the 61+ group receives drug C. People administering the drugs know which subject is receiving which drug, but the subjects do not. Time to relief is measured for each subject. There are obvious confounding variables in this experiment. They are: A) the person administering the drug and the drug type. B) the time to relief and the drug type. C) the age of the subjects and the drug type. D) the subjects and the drug type.
C) the age of the subjects and the drug type
In a pollution study water samples from 100 different locations in Lake Champlain were taken and the level of nitrates was measured. What is the variable of interest? A) Lake Champlain B) a given location in Lake Champlain C) the level of nitrates measured D) the scientist conducting the study
C) the level of nitrates measured
In 1981, 22,071 physicians with no history of heart problems were randomly assigned to receive active aspirin and active beta-carotene, active aspirin and beta-carotene placebo, aspirin placebo and active beta-carotene, or aspirin placebo and beta-carotene placebo. The occurrence of heart incidents were recorded through 1989. Identify the factors in this experiment. A) the 22,071 physicians B) the occurrence or non-occurrence of heart incidents C) the presence or absence of aspirin and/or beta-carotene
C) the presence or absence of aspirin and/or beta-carotene
Two variables are confounded if: A) their effects on the blocking variable can't be measured. B) their effects on the sampling design can't be observed. C) their effects on the response variable can't be distinguished. D) their effects on the experimental design can't be justified.
C) their effects on the response variable can't be distinguished.
The main function of an institutional review board is: A) to review the feasibility of a proposed study. B) to make sure a study stays within budget. C) to protect subjects from possible harm. D) to make sure the results of a study are statistically significant.
C) to protect subjects from possible harm.
In an experiment on a new drug, subjects were randomly assigned to either a placebo or the active drug. In addition, the method of delivery of the drug (pill, skin patch, or nasal mist) was considered. How many treatment groups are there in this experiment? A) 1 B) 2 C) 3 D) 6
D) 6
Which of the following is NOT a property of the standard deviation? A) It has the same units as the data. B) It can never be negative. C) It can be thought of as the average distance from the points to the mean. D) It can never equal zero. E) It is not resistant to outliers.
D) It can never equal zero.
A clinical trial administrator keeps a database of information on participating subjects. Which of the following variables would be considered as quantitative? A) city B) state C) zip code D) None of the above.
D) None of the above.
Which of the following statements correctly describes the complement of event E? A) The complement of event E is the set of all outcomes in the sample space for the experiment. B) The complement of event E is the set of outcomes which are in the sample space but not in event E. C) The complement of event E is the set of all outcomes in event E. D) The complement of event E is the probability that event E does not occur.
D) The complement of event E is the probability that event E does not occur.
Identify the answer choice that is an example of a continuous quantitative variable. A) The year a car was manufactured. B) The country in which the car was manufactured. C) The number of cylinders the cars engine has (4,6,8...). D) The time it takes the car to reach 60 mph from a dead stop. E) The color of the car.
D) The time it takes the car to reach 60 mph from a dead stop.
Researchers studied 29,000 Finnish men, all smokers over the age of 50. Half of the men, selected at random, took vitamin supplements, and the other half took a dummy pill that has no active ingredient. The researchers followed all the men for eight years. At the end of the study, men in the vitamin group were no less likely to have cancer than men in the other group. The statistical name for this design is: A) a simple random sample. B) a multistage sample. C) an observational study. D) a randomized comparative experiment.
D) a randomized comparative experiment.
An experiment that tests a new treatment for early-stage HIV is tested against an already accepted treatment. Fifty early-stage HIV patients are placed in each group. Of the 50 given the new treatment, 40 show improvement within the first month. Of the 50 given the accepted treatment, 35 show improvement within the first month. The population of interest is: A) the 100 patients treated. B) the 75 patients who showed improvement. C) all HIV patients. D) all HIV patients with early-stage HIV.
D) all HIV patients with early-stage HIV.
A psychologist wants to know if adults with normal vision can be fooled by a certain optical illusion. She recruits 50 students with normal vision from her class and finds that 42 of them are fooled by the illusion. The population of interest for this study is: A) the 42 students who were fooled. B) the 50 students who served as subjects. C) all students in her class. D) all adults with normal vision.
D) all adults with normal vision.
In 1981, 22,071 physicians with no history of heart incidents were randomly assigned to receive active aspirin and active beta-carotene, active aspirin and betacarotene placebo, aspirin placebo and active betacarotene, or aspirin placebo and beta-carotene placebo. The occurrence of heart incidents were recorded through 1989. Identify the control group in this experiment. A) active aspirin and active beta-carotene B) active aspirin and beta-carotene placebo C) aspirin placebo and active beta-carotene D) aspirin placebo and beta-carotene placebo
D) aspirin placebo and beta-carotene placebo
How does drinking beer affect the level of alcohol in the blood? Student volunteers at Ohio State University drank different numbers of cans of beer. Their blood alcohol contents were measured 30 minutes later. Identify the response variable. A) student's age B) number of beers drank C) blood alcohol level before drinking beers D) blood alcohol level after drinking beers
D) blood alcohol level after drinking beers
In 1981, 22,071 physicians with no history of heart incidents were randomly assigned to receive active aspirin and active beta-carotene, active aspirin and beta-carotene placebo, aspirin placebo and active betacarotene, or aspirin placebo and beta-carotene placebo. The occurrence of heart incidents were recorded through 1989. Identify the experimental design being used. A) randomized block design B) double-blind design C) matched pairs design D) completely randomized design
D) completely randomized design
A phenomenon is random if: A) individual outcomes are chaotic. B) individual outcomes have no pattern. C) individual outcomes are uncertain but there is a regular distribution of outcomes with a small number of repetitions. D) individual outcomes are uncertain but there is a regular distribution of outcomes with a large number of repetitions.
D) individual outcomes are uncertain but there is a regular distribution of outcomes with a large number of repetitions.
Five different brands of headache tablets were administered to 25 subjects experiencing fevers of 100°F or more. Then the number of hours of relief were recorded. Neither the subjects nor the people administering the tablets knew who received which brand of tablet. This an experiment because: A) it used a random sample of subjects. B) it tested medications. C) the researcher controlled who received which brand of tablet. D) it was double-blind.
D) it was double-blind.
The experimental design principle of making multiple observations for each experimental treatment is called: A) stratified sampling. B) systematic sampling. C) resampling. D) replication. E) sampling with replacement.
D) replication.
Physicians take a sample of smokers and nonsmokers and record the time it takes them to fall asleep on seven consecutive nights. What is the variable of interest? A) the physicians B) the average time it takes to fall asleep on the seven nights C) the smokers and non-smokers D) the amount of time it takes to fall asleep each of the seven consecutive nights
D) the amount of time it takes to fall asleep each of the seven consecutive nights
Any statistical study that uses human subjects requires informed consent. This means that: A) a review board must agree that the study is worthwhile and will not harm the subjects. B) the authors of the study must agree to inform the public of the study results. C) the authors of the study must inform a review board about it and obtain the board's consent to go ahead. D) the nature of the study must be explained in advance to the subjects and they must voluntarily agree to take part.
D) the nature of the study must be explained in advance to the subjects and they must voluntarily agree to take part.
A team of researchers wished to study whether oatmeal reduced bad cholesterol levels in those who ate it. They found 500 adults over age 40 who regularly eat oatmeal or products from oatmeal. They then matched each of these 500 with a similar adult (one of the same gender, within 10 pounds of the same weight, and who exercised roughly the same amount) who did not regularly eat oatmeal or products made from oatmeal. Finally, they measured the bad cholesterol LDL for each adult and compared both groups. This is NOT an experiment because: A) it did not use a random sample of subjects. B) it used matched pairs. C) it was not at least single-blind. D) the researcher did not control whether the adults regularly ate oatmeal or not.
D) the researcher did not control whether the adults regularly ate oatmeal or not
Researchers studied 29,000 Finnish men, all smokers over the age of 50. Half of the men, selected at random, took vitamin supplements, and the other half took a dummy pill that has no active ingredient. The researchers followed all the men for eight years. At the end of the study, men in the vitamin group were no less likely to have cancer than men in the other group. The response variable is: A) whether or not a subject took vitamins. B) 29,000 Finnish men. C) random allocation. D) whether or not a subject developed cancer.
D) whether or not a subject developed cancer.
The General Social Survey (GSS) asks questions to a sample of Americans to determine their opinions about a wide range of topics every other year. In 2006 the GSS survey found that 67% of those sampled were in favor of the death penalty for those convicted of murder. What aspect of statistics is this? A) Design B) Description C) Inference
Description
A social scientist is interested in studying the drinking habits of college students. She asks 1,000 students how many drinks they had last Saturday night. From this survey, she is able to conclude that the average amount of alcoholic beverages consumed by all students in the university last Saturday night was most likely between 0.3 and 2.3 drinks. What aspect of statistics is described in bold type? A) Design B) Description C) Inference
Inference
The General Social Survey asks questions to a sample of Americans to determine their opinions about a wide range of topics every other year. Using data from the 2006 survey and statistical methods it can be deduced that the percentage of all Americans that favor the death penalty for those convicted of murder is most likely between 65.19% and 68.70%. What aspect of statistics is this? A) Design B) Description C) Inference
Inference
