Stats 121 Quiz Questions 1-11
In a random digit telephone survey, neither people who are homeless nor people who only own a cell phone have land-line telephones that can be called with random digit dialing. What type of bias is this? A. Undercoverage bias B. Non-response bias C. Response bias due to respondent lying or deliberately giving incorrect information D. Response bias due to question wording E. Response bias due to interviewer influences
A. Undercoverage bias
Probability is a measure of how likely an event is to occur. Choose the probability that best matches the following statement: "This event is impossible; it cannot occur." A. 0.0 B. 0.05 C. 0.3 D. 0.6 E. 0.95 F. 1.0
A. 0.0
A high school teacher wants more information about her students' study habits. She writes each of her students' names on an identical slip of paper and places them in a hat. After mixing up the papers, she selects 30 students from the hat. She then asks the question, "How many hours a week do you study outside of school, 0-3, 4-6, or more than six?" and records their responses. What type of sample is this? A. A simple random sample B. A stratified sample C. A multistage sample D. A convenience sample
A. A simple random sample
computer manufacturer has just received a shipment of 8000 computer chips. In order to ensure that the shipment meets their quality standards, they want to sample a few chips and make a detailed examination of the sample. The chips are packaged individually and have serial numbers. If they use a statistical software package to randomly select serial numbers for 20 chips for inspection, what type of sampling is this? A. A simple random sample. B. A stratified sample. C. A convenience sample. D. A multistage sample.
A. A simple random sample.
R.A. Fisher, a famous statistician, describes a well-known design in his book, Design of Experiments. Five varieties of wheat were compared to determine which gave the highest yield in bushels per acre. Eight farms were available for planting. Each farm was divided into five plots. For each farm, the five varieties were randomly assigned to the five plots with one variety per plot. The varieties were planted on their assigned plots and their yields were measured and compared. How was randomization incorporated into this study? A. All five varieties were randomly assigned to the five plots at each farm. B. The five varieties were randomly assigned to the eight farms - three varieties were planted twice and two varieties only once. C. It was not incorporated. The wheat seeds were not randomly selected from the population of wheat seeds.
A. All five varieties were randomly assigned to the five plots at each farm.
We sometimes hear that marriage is good for your career. A sample of 8235 managers and professionals employed by a specific large manufacturing firm were asked their marital status (married, single, widowed, or divorced) and their annual income. The mean annual income was then calculated for each of the four marital status groups. What is the population? A. All managers and professionals employed by this manufacturing firm. B. The mean annual income for all managers and professionals employed by this manufacturing firm. C. The 8235 managers and professionals who were interviewed. D. All married managers and professionals from this large manufacturing firm.
A. All managers and professionals employed by this manufacturing firm.
Students at a particular university are able to evaluate professors on a five point scale (a score of 1 meaning poor teaching and a score of 5 meaning excellent teaching, with answers limited to whole numbers). What type of random variable is professor evaluation an example of? A. Discrete B. Continuous C. It is impossible to say given the information provided.
A. Discrete
Is the right hand generally stronger than the left in right-handed people? You can crudely measure hand strength by placing a bathroom scale on a shelf with the end protruding, then squeezing the scale between the thumb below and the four fingers above it. The reading of the scale shows the force exerted. Which of the following best describes the design of a matched pairs experiment to compare the strength of the right and left hands using 10 right-handed people as subjects? A. Each subject squeezes the scale twice: once with his right hand and once with his left hand with the order randomly determined. Scale readings are then compared. B. Each of the ten right-handed people squeeze the scale. Their scale readings are compared with the scale readings of each of the ten left-handed people. C. Five of the right-handed people squeeze the scale with their right hand, and the other five with their left hand. Scale readings are then compared. D. Each subject squeezes the scale first with his right hand and then second with his left hand. Scale readings are then compared.
A. Each subject squeezes the scale twice: once with his right hand and once with his left hand with the order randomly determined. Scale readings are then compared.
1772 1666 1362 1460 1867 1439 1614 Suppose the first number in the data set was 1972 instead of 1772. How would this change the value of the mean? A. Increase mean B. Would not change the mean C. Decrease mean
A. Increase median
High school students are selected by choosing at random several of the city's high schools and then randomly selecting some of the students from those selected high schools. What sampling technique is being used? A. Multistage sampling. B. simple random sampling. C. stratified sampling. D. convenience sampling.
A. Multistage sampling
To investigate the effects of the drug phen-fen, 200 women in the 30-40 age range who had used the drug for at least one year were located. 200 women of the same age group who had not used the drug were also located. The incidence of heart valve abnormality was compared between the two groups. What type of study is this? A. Observational Study B. Randomized Controlled Experiment C. Randomized Block Experiment D. Matched Pairs Experiment
A. Observational Study
On August 27, 1995, an article in the Los Angeles Times reported that in its survey of 3297 California adults, 2780 (83.4%) had health insurance coverage. These results have a margin of error of ± 1.4%. What type of study is being described? A. Observational study B. Experiment C. Neither an observational study nor an experiment
A. Observational study
In an email survey, students were asked, "During the past week, how many nights did you go to sleep past midnight?" What type of variable is "number of nights going to sleep past midnight"? A. Quantitative B. Categorical
A. Quantitative
What type of data are displayed in stemplots, dotplots, and histograms? A. Quantitative data B. Categorical data
A. Quantitative data
The mean and median selling price of existing single-family homes sold in October 2005 were (in no particular order) $216,200 and $265,000. Which of the following most accurately explains which is the mean and which is the median and why? (Hint: Although most single-family homes are around this price range, there are a small number of multi-million dollar homes.) A. The median is $216,200 and the mean is $265,000 because economic variables tend to be skewed to the right, pulling the mean above the median. B. The median is $265,000 and the mean is $216,200 because economic variables tend to be skewed to the left, pulling the mean below the median. C. The median is $216,200 and the mean is $265,000 because economic variables tend to be skewed to the left, pulling the mean above the median. D. The median is $265,000 and the mean is $216,200 because economic variables tend to be skewed to the right, pulling the mean below the median. E. The median is $265,000 and the mean is $216,200 because $216,200 is less "round" than $265,000, and in calculating the average we use the division operation which leads to a less round result.
A. The median is $216,200 and the mean is $265,000 because economic variables tend to be skewed to the right, pulling the mean above the median.
In statistics, how do we define the probability of an event? A. The relative frequency with which the event occurs in a long series of trials. B. The ratio of one over the total number of possible outcomes.
A. The relative frequency with which the event occurs in a long series of trials.
A shoe manufacturer wanted to determine which type of material, "Material X" or "Material Y", to use on the soles of their shoes to get maximum wear. Twenty teenage boys wore one shoe with each type of sole. For each young man, a coin was tossed; if heads, "Material X" would go on the right shoe and "Material Y" on the left. If tails, "Material X" would go on the left shoe and "Material Y" on the right. After wearing these shoes for four months, the thickness of the sole of each shoe was measured. Referring to the question above, was replication incorporated? A. Yes, because each treatment group had 20 subjects B. Yes, because the experiment was repeated on another set of boys C. No, because the experiment was not repeated on another set of boys D. No, because there was more than one subject in the experiment
A. Yes, because each treatment group had 20 subjects
Because more questions about statistics have been added to the state exam, a school district decided to add a probability-statistics unit to their ninth-grade general mathematics course. To determine whether the unit will have an impact on scores on the state exam, all ninth-grade students enrolled in a general mathematics course in the largest high school in the school district were randomly allocated into two groups. One group of 281 students received instruction in a new probability and statistics unit in addition to the traditional instruction; the other group of 311 students received only traditional instruction. Students in both groups were given the state exam at the end of ninth grade to determine whether the group receiving additional instruction in probability and statistics had a higher average score than the group receiving just traditional instruction. Does this study incorporate the principle of control or comparison? A. Yes, because the group of students receiving only traditional instruction can be considered a control or comparison group. The group of students receiving the additional instruction of probability-statistics can be considered the active treatment group. B. No, because there was not a group of students who did not receive any instruction.
A. Yes, because the group of students receiving only traditional instruction can be considered a control or comparison group. The group of students receiving the additional instruction of probability-statistics can be considered the active treatment group.
Because more questions about statistics have been added to the state exam, a school district decided to add a probability-statistics unit to their ninth-grade general mathematics course. To determine whether the unit will have an impact on scores on the state exam, all ninth-grade students enrolled in a general mathematics course in the largest high school in the school district were randomly allocated into two groups. One group of 281 students received instruction in a new probability and statistics unit in addition to the traditional instruction; the other group of 311 students received only traditional instruction. Students in both groups were given the state exam at the end of ninth grade to determine whether the group receiving additional instruction in probability and statistics had a higher average score than the group receiving just traditional instruction. Does the study described incorporate the principle of replication? A. Yes, because there were 281 students in one group and 311 in the other group (more than one individual per treatment group) B. No, because the study was not repeated another year (the experiment only happened once)
A. Yes, because there were 281 students in one group and 311 in the other group (more than one individual per treatment group)
Because more questions about statistics have been added to the state exam, a school district decided to add a probability-statistics unit to their ninth-grade general mathematics course. To determine whether the unit will have an impact on scores on the state exam, all ninth-grade students enrolled in a general mathematics course in the largest high school in the school district were randomly allocated into two groups. One group of 281 students received instruction in a new probability and statistics unit in addition to the traditional instruction; the other group of 311 students received only traditional instruction. Students in both groups were given the state exam at the end of ninth grade to determine whether the group receiving additional instruction in probability and statistics had a higher average score than the group receiving just traditional instruction. Does the study described incorporate the principle of randomization? A. Yes, because we are told that "students . . . were randomly allocated . . ." B. No, because students registered for whichever section they wanted.
A. Yes, because we are told that "students . . . were randomly allocated . . ."
Question 1: How satisfied are you with your current job: very satisfied, somewhat satisfied, somewhat dissatisfied, very dissatisfied? Question 2: What do you think can be improved about your job? Are these examples of open or closed questions? A. Question 1 is an open question and Question 2 is a closed question B. Question 1 is a closed question and Question 2 is an open question C. Both are open questions D. Both are closed questions
B. Question 1 is a closed question and Question 2 is an open question
Choose the probability that best matches the following statement: "This event is very unlikely, but it will occur once in a while in a long sequence of trials." A. 0.0 B. 0.05 C. 0.3 D. 0.6 E. 0.95 F. 1.0
B. 0.05
The college of humanities in a large university was accused of discrimination in their faculty hiring. Twenty records of the recent female applicants who were not hired and twenty records of recent male applicants who were not hired were randomly selected and compared with the records of the recent hires. What type of sampling design is this? A. A simple random sample. B. A stratified sample. C. A convenience sample. D. A multistage sample.
B. A stratified sample.
Which of the following potentially allows researchers to establish that the treatments "cause" changes in the responses? A. An observational study B. An experiment
B. An experiment
study of computer-assisted learning examined the learning of "Blissymbols" by children. Blissymbols are pictographs (think of Egyptian hieroglyphs) that are sometimes used to help learning-impaired children communicate. The researcher designed two computer lessons that taught the same content using the same examples. One lesson required the children to interact with the material, while in the other the children controlled only the pace of the lesson. Call these two styles "Active" and "Passive", respectively. Children were assigned at random to Active and Passive groups. After the lesson, the computer presented a quiz that asked the children to identify 56 Blissymbols. What type of study is this? A. Observational study B. Experiment
B. Experiment
R.A. Fisher, a famous statistician, describes a well-known design in his book, Design of Experiments. Five varieties of wheat were compared to determine which gave the highest yield in bushels per acre. Eight farms were available for planting. Each farm was divided into five plots. For each farm, the five varieties were randomly assigned to the five plots with one variety per plot. The varieties were planted on their assigned plots and their yields were measured and compared. What type of study is this? A. Observational study - multistage sample B. Experiment - randomized block design C. Experiment - randomized controlled experiment D. Observational study - simple random sample E. Observational study - stratified sample
B. Experiment - randomized block design
In studies of worker productivity, it has been noticed that any change in the work environment together with the knowledge that a study is underway will produce a short-term increase in productivity. This is known as A. placebo effect. B. Hawthorne effect. C. diagnostic bias D. non-compliance.
B. Hawthorne effect
Which type of graphical display is used for large sets of quantitative data? A. Stem and Leaf Plot B. Histogram C. Dot Plot
B. Histogram
What is the final step in the Big Picture of statistics, as outlined in class? A. Exploratory data analysis B. Inference C. Produce data D. Probability
B. Inference The four steps in the Big Picture of statistics are: 1. Producing Data 2. Exploratory Data Analysis 3. Probability 4. Inference
Medical experiments are often double blind in nature. What does this mean? A. The subjects in the control group receive a placebo treatment. B. Neither the subject nor the person evaluating the subject (the doctor or nurse) knows which treatment the subject receives. C. All data on individuals are kept confidential D. Subjects are randomly assigned to treatments without the doctor's knowing how the randomizing was done.
B. Neither the subject nor the person evaluating the subject (the doctor or nurse) knows which treatment the subject receives.
Suppose you have played a game many, many times---winning sometimes and losing sometimes. Can you use the results of playing the game to predict with absolute certainty whether you will win the game on the next try? A. Yes B. No
B. No
Which of the following is a categorical variable? A. Height B. Phone Number C. Mile time D. Book costs
B. Phone number
Which graph is not used to display quantitative data? A. Histogram B. Pie chart C. Stem and Leaf Plot D. Dot Plot
B. Pie Chart
The group we want to study or learn something about is known as the A. sample. B. population. C. individual. D. group.
B. Population
What is the first step in the Big Picture of Statistics? A. Exploratory Data Analysis B. Producing Data C. Inference D. Probability
B. Producing Data
Administrators at Cosmo University are becoming more and more alarmed at the number of hours students work per week. In order to examine the relationship between the number of hours worked per week in a semester and that semester's GPA, one administrator surveyed 300 students currently attending the university. What type of variable is the number of hours worked per week? Referring to the study in question 9, what type of variable is GPA? A. Categorical B. Quantitative
B. Quantitative
Administrators at Cosmo University are becoming more and more alarmed at the number of hours students work per week. In order to examine the relationship between the number of hours worked per week in a semester and that semester's GPA, one administrator surveyed 300 students currently attending the university. What type of variable is the number of hours worked per week? A. Categorical B. Quantitative
B. Quantitative
Because of concerns about employee obesity and related health problems, a very large company conducted a study to compare two weight-reducing programs (low-carb diet and low-fat diet). Forty employees volunteered to participate in the study for a 10-week period. Half of the employees were randomly assigned to the low-carb diet and the other half randomly assigned to the low-fat diet. What type of study is this? A. Observational Study B. Randomized Controlled Experiment C. Randomized Block Experiment D. Matched Pairs Experiment
B. Randomized Controlled Experiment
What is the major difference between an observational study and an experiment? A. Subjects choose their treatment in an experiment. B. Researchers assign treatments to subjects in an experiment. C. Experiments frequently have confounding between two variables in their effect on the response variable.
B. Researchers assign treatments to subjects in an experiment.
Which of the following describes a valid sampling procedure? A. Interviewer uses a set of personal criteria to pick respondents B. Respondents are chosen by an impersonal chance device C. Each respondent chooses whether or not to respond D. The first 50 people at a shopping mall are selected
B. Respondents are chosen by an impersonal chance device
With the "Let's Make a Deal" game show, what strategy should contestants use? A. Stay with the door that was originally picked. B. Switch to the other closed door. C. It doesn't make a difference as to which strategy he or she uses.
B. Switch to the other closed door.
What does the statistical term "population" refer to? A. It always refers to the United States population. B. It refers to the group we want to study or learn something about. C. It refers to a subset of the group we want to study. D. It refers to a set of principles that guide the study of statistics.
B. The group we want to study or learn something about.
When are two variables said to be confounded? A. When both have the same effect on the response variable. B. When their effects on the response variable cannot be distinguished from each other. C. When both variables are explanatory variables. D. When both variables are treatment variables.
B. When their effects on the response variable cannot be distinguished from each other.
1772 1666 1362 1460 1867 1439 1614 Suppose the first number in the data set was 1972 instead of 1772. How would this change the value of the median? A. Increase median B. Would not change the median C. Decrease median
B. Would not change the median
R.A. Fisher, a famous statistician, describes a well-known design in his book, Design of Experiments. Five varieties of wheat were compared to determine which gave the highest yield in bushels per acre. Eight farms were available for planting. Each farm was divided into five plots. For each farm, the five varieties were randomly assigned to the five plots with one variety per plot. The varieties were planted on their assigned plots and their yields were measured and compared. Was using the eight farms as blocks appropriate? A. Yes, because each farm was large. B. Yes, because it removes lurking variables from farm to farm. C. No, because each fertilizer should be a block.
B. Yes, because it removes lurking variables from farm to farm.
A sample of 12th-grade students who took the National Assessment of Education Progress year 2000 mathematics test had a mean score of 250. What is the population? A. all 12th-grade students B. all 12th-grade students who took the National Assessment C. the mean score for all 12th-grade students who took the National Assessment of Educational Progress year 2000 mathematics test D. 12th-grade students who took the National Assessment of Educational Progress year 2000 mathematics test who received a score of 250
B. all 12th-grade students who took the National Assessment
Which of the following sets of four numbers has the largest standard deviation? A. 0, 0, 1, 1 B. 4, 4, 5, 5 C. 0, 0, 9, 9 E. 0, 1, 8, 9
C. 0, 0, 9, 9
A couple plans to have three children. There are eight possible arrangements of girls and boys. For example, GGB means the first two children are girls and the third child is a boy. All eight arrangements are (approximately) equally likely. Write down all eight arrangements of the sexes of three children. Based on the eight arrangements, what is the probability of obtaining any one of these arrangements? A. 0.0833 B. 0.100 C. 0.125 D. 0.250 E. 0.375 F. 0.500
C. 0.125
Choose the probability that best matches the following statement: "This event is less likely to occur, but it is not extremely unlikely." A. 0.0 B. 0.05 C. 0.30 D. 0.60 E. 0.95 F. 1.0
C. 0.30
The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. Approximately what percentage of students spent between $195 and $255? A. 60% B. 47.5% C. 81.5% D. 95%
C. 81.5%
Educators in California are concerned about a recent newspaper article reporting that students in the United States are falling behind students in other nations in their math skills. They decide to sample 10th grade students throughout the state and test their mathematics skills. They first randomly select 10 school districts. From each of these 10 school districts they randomly select three high schools. From these 3 high schools they randomly select 10 students and test them. What type of sample is this? A. A simple random sample B. A stratified sample C. A multistage sample
C. A multistage sample
A large university in the western United States wants to survey the faculty regarding its plan to combine the spring and summer terms into one semester. It randomly selects 5 colleges on its campus and from each of these colleges, randomly selects 4 departments. Within the chosen departments, 4 faculty members are selected to be included in the sample. What type of sampling design is this? A. A simple random sample. B. A stratified sample. C. A multistage sample. D. A convenience sample.
C. A multistage sample.
A popular magazine is interested in the average amount of time that their readers spend on the internet each day. They randomly survey 100 of their female readers and 100 of their male readers and ask them about their average internet use. What type of sample is this? A. A convenience sample B. A volunteer sample C. A stratified sample D. A Simple Random Sample
C. A stratified sample`
What does the distribution of a random variable give us? A. The measure of the amount of deviation of the random variable about the mean. B. A density curve whose x values are always positive. C. All possible values of the random variable and how often they occur.
C. All possible values of the random variable and how often they occur.
Because more questions about statistics have been added to the state exam, a school district decided to add a probability-statistics unit to their ninth-grade general mathematics course. To determine whether the unit will have an impact on scores on the state exam, all ninth-grade students enrolled in a general mathematics course in the largest high school in the school district were randomly allocated into two groups. One group of 281 students received instruction in a new probability and statistics unit in addition to the traditional instruction; the other group of 311 students received only traditional instruction. Students in both groups were given the state exam at the end of ninth grade to determine whether the group receiving additional instruction in probability and statistics had a higher average score than the group receiving just traditional instruction. Who are the subjects in this study? A. The classrooms receiving the traditional instruction. B. The classrooms receiving the new instruction. C. Ninth-grade students enrolled in a general mathematics course. D. All high school students.
C. Ninth-grade students enrolled in a general mathematics course
What is an advantage of using a stem and leaf plot, rather than a histogram? A. Stem plots are best for very large sets of data and histograms are not B. Stem plots only work for categorical sets of data C. Stem plots can show exact values, where histograms are more approximate D. Stem plots can show the shape of the data, but histograms cannot
C. Stem plots can show exact values, where histograms are more approximate
The nonprofit group Public Agenda conducted telephone interviews with parents of high school children. Interviewers chose equal numbers of black, white, and Hispanic parents by randomly selecting from within each race using student records. One question asked was "Are the high schools in your state doing an excellent, good, fair, or poor job, or do you not know enough to say?" What type of sample is this? A. Convenience Sample B. Simple random sample C. Stratified sample D. Multistage sample
C. Stratified sample
Referring to the study in question 5, what is the sample? A. All managers and professionals employed by this manufacturing firm. B. The mean annual income for all managers and professionals employed by this manufacturing firm. C. The 8235 managers and professionals from this large manufacturing firm. D. All married managers and professionals employed by this manufacturing firm.
C. The 8235 managers and professionals from this large manufacturing firm.
Two hundred twenty-eight children in a study were assigned to one of three groups. Group one was required to consume 5 mg of caffeine or less each day, Group two was required to consume 5-20 mg of caffeine a day, and Group three was required to consume more than 20 mg of caffeine per day. At the end of three weeks, their parents reported the average amount of sleep their child got each night. What is the explanatory variable? A. The average amount of sleep a child got each night. B. Getting more than 20 mg of caffeine per day. C. The amount of caffeine a child got each day. D. Those who were in group three.
C. The amount of caffeine a child got each day.
Because more questions about statistics have been added to the state exam, a school district decided to add a probability-statistics unit to their ninth-grade general mathematics course. To determine whether the unit will have an impact on scores on the state exam, all ninth-grade students enrolled in a general mathematics course in the largest high school in the school district were randomly allocated into two groups. One group of 281 students received instruction in a new probability and statistics unit in addition to the traditional instruction; the other group of 311 students received only traditional instruction. Students in both groups were given the state exam at the end of ninth grade to determine whether the group receiving additional instruction in probability and statistics had a higher average score than the group receiving just traditional instruction. What is the explanatory variable in this study? A. The exam taken at the end of the year. B. The high school a student attended. C. The type of general mathematics instruction received: new instruction or traditional instruction. D. The new instruction.
C. The type of general mathematics instruction received: new instruction or traditional instruction.
What is a correct description of the median of a distribution that is described by a density curve? A. The value in the data set that occurs with the highest frequency. B. The point that is intermediate between interquartile range and standard deviation. C. The value that divides the area of the density curve in half. D. The point at which the distribution "balances".
C. The value that divides the area of the density curve in half.
What is the purpose of statistics? A. To mislead others. B. To find the right answer. C. To convert data into useful information. D. All of the above.
C. To convert data into useful information.
The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. Below what value are approximately 97.5% of the students? A. $195 B. $215 C. $255 D. $275 E. $295
D. $275
What is the median for the following set of metabolic rates? 1772 1666 1362 1460 1867 1439 1614 A. 1640.0 B. 1666.0 C. 1450.5 D. 1614.0
D. 1614.0
A reporter for the university newspaper wants to find out the opinions that all BYU students have about the university health center. During a class break, he goes to the health center, contacts a few students as they exit, and asks them to fill out a survey. What type of sample is this? A. A simple random sample B. A stratified sample C. A multistage sample D. A convenience sample
D. A convenience sample
A shoe manufacturer wanted to determine which type of material, "Material X" or "Material Y", to use on the soles of their shoes to get maximum wear. Twenty teenage boys wore one shoe with each type of sole. For each young man, a coin was tossed; if heads, "Material X" would go on the right shoe and "Material Y" on the left. If tails, "Material X" would go on the left shoe and "Material Y" on the right. After wearing these shoes for four months, the thickness of the sole of each shoe was measured. What type of study is this? A. A randomized controlled experiment. B. A simple random sample. C. A voluntary response sample. D. A matched pairs experiment.
D. A matched pairs experiment.
A television station is interested in predicting whether or not voters are in favor of an increase in the state sales tax. It asks its viewers to phone in and indicate whether they support or are opposed to the proposed increase in order to generate additional revenue for education. What type of sampling design is this? A. A simple random sample. B. A stratified sample. C. A multistage sample. D. A voluntary response sample.
D. A voluntary response sample
Which of the following is NOT a valid probability sample? A. A simple random sample B. A stratified sample C. A multistage sample D. A voluntary response sample
D. A voluntary response sample
Statistics is a process where we do which of the following? A. Collect data B. Summarize data C. Interpret data D. All of the above
D. All of the above
Why do we sample? A. A census is too expensive. B. A census is time consuming. C. A census may be impractical. D. All of the above.
D. All of the above
Why might collecting data from a sample be preferred over collecting data from a population? A. Less expensive. B. Less time consuming. C. Collecting data from the entire population may be impossible. D. All of the above.
D. All of the above
Three of the following are correct statements about probabilities and one statement is incorrect. Which statement is NOT correct? A. All probabilities must be between zero and one inclusive. B. The probability that an event does not occur equals one minus the probability that the event does occur. C. The sum of the probabilities from all possible outcomes equals one. D. If two events cannot occur simultaneously, then the probability that either occurs cannot be computed.
D. If two events cannot occur simultaneously, then the probability that either occurs cannot be computed.
What is a sample? A. It is a different term for population. B. It is everyone in the United States. C. It is a part of the inference step in the Big Picture of Statistics. D. It is a subgroup of the population.
D. It is a subgroup of the population.
n educational software company wants to compare the effectiveness of its computer animation for teaching about supply and demand curves with that of a textbook presentation. The company tests the economic knowledge of a number of first-year college students, then randomly divides them into two groups. One group uses the animation, and the other studies the text. The company retests all the students and compares the increase in economic understanding in the groups. Is the study described above an experiment? Why or why not? A. It is not an experiment because there is no attempt to influence the responses on the tests on economic understanding. B. It is not an experiment because it does deliberately impose a condition on the first-year college students. C. It is an experiment because it only measures students' economic knowledge. D. It is an experiment because the students were randomly assigned to either the animation group or the textbook group.
D. It is an experiment because the students were randomly assigned to either the animation group or the textbook group.
Suppose a researcher is interested in the average ACT score for high school students in Illinois. She randomly selects 20 counties and then randomly selects 3 high schools from each selected county and then asks each student in the selected high schools what their ACT score was. What kind of sample is this? A. Simple random sample (SRS) B. Stratified sample C. Convenience sample D. Multistage sample
D. Multistage sample
Which one of the following is NOT a consequence of lack of randomization? A. Results could be biased B. A lurking variable is likely confounded with the explanatory variable C. Laws of probability cannot be used to measure uncertainty in conclusions D. Not enough individuals will be available to measure chance variation
D. Not enough individuals will be available to measure chance variation
Which of the following is not part of the Big Picture of Statistics? A. Collecting data. B. Summarizing data. C. Interpreting data. D. Publishing research results.
D. Publishing search results.
A. All college students. B. The college students who believe in a higher power. C. The 107 college students who pray at least once in a while. D. The 127 college students who were interviewed.
D. The 127 college students who were interviewed.
What is the symbol for the sample mean? A. μ B. M C. s D. x̄
D. x̄
A couple plans to have three children. There are eight possible arrangements of girls and boys. For example, GGB means the first two children are girls and the third child is a boy. All eight arrangements are (approximately) equally likely. Write down all eight arrangements of the sexes of three children. Let X be the number of girls the couple has. Based on the eight arrangements, what is the probability that X = 2? A. 0.0833 B. 0.100 C. 0.125 D. 0.250 E. 0.375 F. 0.500
E. 0.375
Choose the probability that best matches the following statement: "This event is extremely likely, but occasionally it will not occur in a long sequence of trials." A. 0 B. 0.05 C. 0.30 D. 0.60 E. 0.95 F. 1.0
E. 0.95
o test the effectiveness of using a dab of honey to prevent infection in a cut, parents of children in a childcare facility were instructed to wash the wounds of their children with soap and water and then place a dab of honey on the cut. Each cut was then monitored for infection. At the end of the study, the percentage of cuts that became infected was computed. Why is this NOT a valid experiment? A. There is no randomization. B. There is no blinding - parents may use more care and those monitoring for infection may be less stringent in their diagnosis. C. There is no control group that gets a placebo for comparison. D. Parents may be more careful of the cuts of their children since they know they are in an experiment. E. All of these answers are correct.
E. All of these answers are correct.
What type of bias results when people respond differently to questions asked by male interviewers than they do to questions asked by female interviewers? A. Undercoverage bias B. Nonresponse bias C. Response bias due to respondent lying or deliberately giving incorrect information D. Response bias due to question wording E. Response bias due to interviewer effect
E. Response bias due to interviewer effect
True or False: Convenience sampling is a type of probability sampling design.
False
True or False: Taking a valid simple random sample eliminates all biases, including question wording bias and interviewer bias.
False
True or False: The Field of Statistics starts when we begin summarizing data.
False
True or False: The statistical term population can only refer to people.
False
True or False: We can establish causation whenever a valid sample (simple random sample, stratified sample, multistage sample, etc.) is taken.
False
An experiment that doesn't incorporate randomization is NOT a valid experiment. A. True B. False
True
True or False: All statistical summaries and conclusions should be reported in context.
True
True or False: Cause and effect relationships cannot be established from observational studies because the explanatory variable is usually confounded with lurking variables.
True
True or False: Inference is the way that we are allowed to draw conclusions about the population based on the data collected about the sample.
True
True or False: Outliers "inflate" standard deviation.
True
True or False: Probability is a way to measure or quantify uncertainty.
True
True or False: The Law of Large Numbers states that as the number of trials increases, the relative frequency of an event gets closer and closer to the theoretical probability.
True
True or False: The placebo effect happens when subjects improve because they have confidence in the medical provider and hope in the medication, even when they may not be receiving the treatment.
True
True or False: When sampling from the population of interest, it is a good idea to have a representative sample.
True
True or False: Without random selection, we cannot appropriately apply the laws of probability to perform inference.
True
When we use a randomized block design we want the subjects within each "block" to be similar but they should be different from block to block.
True
A sample of 12th-grade students who took the National Assessment of Education Progress year 2000 mathematics test had a mean score of 250. Referring to the previous question, the variable test scores is quantitative. True False
True
