WorksheetsAP Stats Unit 4 Test
Total questions: 22
Worksheet time: 11mins
The organizers of the annual “Comic-Con” convention would like to estimate the average number of “Comic-Con” conventions that an attendee at this year’s convention has previously attended. The organizers randomly select 100 attendees at this year’s “Comic-Con” convention, and ask them how many “Comic-Con” conventions they have attended previously. All of those asked the question responded. Which of the following describes the sample taken, and the population to which it would be most reasonable to generalize the results?
A) The sample is all “Comic-Con” convention attendees this year, and the population is all fans of “Comic-Con”.
B) The sample is all “Comic-Con” convention attendees this year, and the population is the 100 “Comic-Con” convention attendees who answered the question.
C) The sample is the 100 “Comic-Con” convention attendees who answered the question, and the population is all fans of “Comic-Con”.
D) The sample is the 100 “Comic-Con” convention attendees who answered the question, and the population is all people who attended the “Comic-Con” convention this year.
E) The sample is the average number of “Comic-Con” convention an attendee has previously attended, and the population is all “Comic-Con” convention attendees this year.
Carnival Cruise Lines would like to gather information about passenger preferences in potential new shore excursions (day trips while the cruise ship is docked in a port) on its cruises in the Western Caribbean. They obtain the passenger lists for each of their hundreds of Western Caribbean cruises in a given year. They then randomly select 10 such cruises, and survey every passenger on each selected cruise.
Simple random sample
Stratified random sample
Cluster sample
Convenience sample
Voluntary response sample
The producers of a popular television talent show would like to have the viewers of a live show decide which acts will move on to the next round of the competition. At the conclusion of the live show, they ask viewers to vote for their favorite act by going to a website and registering their preference. The identity of each device used to vote is recorded, so it may only be used once to vote. The results of the voting are shared with all viewers the following day. Which of the following is a potential source of bias resulting from the use of this voting method?
The viewers that chose to vote may have different opinions about the acts that performed on the show than viewers that did not choose to vote.
Viewers with strong opinions about the acts that performed in the live show are more likely to vote than viewers without strong opinions about the acts that performed.
Viewers that vote with multiple devices are more likely to see their favorite acts move on in the competition than viewers who can only vote with one single device.
Choices A, B, and C above are all potential sources of bias.
None of the choices A, B, and C above are potential sources of bias.
Five sampling methods (A, B, C, D, and E) are being evaluated. The true value of the parameter that is being estimated is 10. Simulations of 100 samples, each of size n, are drawn from the population using the five different sampling methods and the estimate of the parameter is recorded for each sample. Which sampling method produces the best estimates for the parameter?
A)
B)
C)
D)
E)
A research team is investigating the effectiveness of two new medicated creams for eczema, X and Y. Two hundred volunteers will be assigned at random to groups. The first group will be given cream X at low dose, the second will be given cream X at high dose, the third will be given cream Y at low dose, the fourth will be given cream Y at high dose, and the fifth will be given a placebo cream that looks, smells, and feels like the other creams, but just does not have any active ingredient that affects eczema. Each individual will be evaluated at the beginning and end of the study to determine the degree to which their eczema has improved. How many treatments were used in this experiment?
A) 2
B) 4
C) 5
D) 40
E) 200
An experiment was performed comparing a new weight loss injection with a placebo treatment. 60 volunteers were obtained and classified according to how many pounds they were currently overweight. The 30 most overweight subjects were given the injection, and the 30 least overweight subjects were given the placebo. The mean amount of weight lost was greater for the subjects who received the injection than for those who received the placebo. Which of the following statements is false?
This study compares at least two treatment groups.
This study utilizes random assignment of treatments to experimental units.
This study displays replication (more than one experimental unit in each treatment group).
This study imposes a different treatment on each group.
This study utilizes a voluntary response sample.
Practicing yoga and taking antidepressant medication are two treatments that have been proposed to help relieve symptoms of post traumatic stress disorder (PTSD). An experiment will be performed in which volunteer patients who are experiencing symptoms of PTSD and who are interested in exploring these two treatments are randomly assigned to either practice yoga for 60 minutes per day, or take an antidepressant medication each day for three months. At the beginning and at the end of the experiment, each patient will be evaluated by a PTSD professional, who does not know which treatment the patient received. This professional will determine the change in mental health state of each patient to determine how much improvement has been made during the course of the experiment. How can the concept of blinding be used in this experiment?
Neither the patient, nor the PTSD professional can be blind to the treatment.
The patient can be blind to the treatment, but the PTSD professional cannot.
The PTSD professional can be blind to the treatment, but the patient cannot.
Both the PTSD professional and the patient can be blind to the treatment.
It is not possible to utilize blinding in this experiment because no control group was used.
A company that produces fertilizer is interested in determining if their newly developed fertilizer is more effective at increasing the yield of strawberry plants than their standard fertilizer. A plot of land is prepared and divided into 100 equally sized squares that are considered the same in every way, and one strawberry plant is planted in each square. Fifty randomly selected squares will be treated with the newly developed fertilizer, and the other 50 squares will be treated with the standard fertilizer. At the end of the growing season, the average yield of the strawberry plants that were given the newly developed fertilizer will be compared to the average yield of the strawberry plants that were given the standard fertilizer. Which of the following describes the design of this experiment?
A randomized block design, because two fertilizers were compared in this experiment.
A matched pairs design, because two fertilizers were compared in this experiment.
A matched pairs design, because each fertilizer was randomly assigned to treat 50 strawberry plants.
A completely randomized design, because each fertilizer was randomly assigned to treat 50 strawberry plants.
A stratified design, because the plot was divided into 100 equally sized squares before the fertilizer was randomly assigned.
A “guardian cap” is a padded cover that is worn over a football helmet that developers claim will decrease the risk and severity of concussion for the player upon severe impact. Some teams have considered requiring the guardian cap for players in positions that more often receive severe contact (offensive linemen, defensive linemen, linebackers and tight ends). An experiment investigating the effectiveness of the guardian cap will use a randomized block design. Which of the following should be considered when setting up blocks for this experiment?
Players should be assigned at random to either wear a guardian cap over their helmet while playing, or to wear a helmet without a guardian cap while playing.
All offensive players should wear a guardian cap over their helmet while playing, and all defensive players should wear a helmet without a guardian cap while playing.
All players that play certain positions that tend to have more impact should wear a guardian cap over their helmet while playing, and all players in other positions that tend to have less impact should wear a helmet without a guardian cap while playing.
Players should be blocked by football position played because players at different positions tend to receive different amounts of impact to the head while playing.
It is not possible to use blocking in this experiment because players will know if they are wearing a guardian cap over their helmet while playing or if they are wearing a helmet without a guardian cap while playing.
A study was conducted that investigated the effect of brisk walking on retention of visceral fat around the midsection (fat found in the spaces surrounding internal organs such as the liver and intestines). Researchers randomly assigned 60 adult volunteers with significant amounts of visceral fat to one of two groups. Both groups met with a nutritionist before the study and followed a healthy diet for the duration of the study. In addition, the first group was instructed to walk at a brisk pace for 30 minutes each day, while the second group was instructed to go about their daily activities as normal. At the end of six months, the decrease in visceral fat was measured for each participant. It was determined that the walking group lost a significantly higher percentage of visceral fat than the other group.
There is convincing evidence suggesting that brisk walking causes a decrease in visceral fat, and the results can be generalized to all adults.
There is convincing evidence suggesting that brisk walking causes a decrease in visceral fat, and the results can be generalized to all adults similar to the ones in this study.
There is convincing evidence suggesting that brisk walking caused a decrease in visceral fat for the participants in the study, and the results can be generalized to all adults who walk briskly.
Cause and effect cannot be established, but there is convincing evidence of an association between brisk walking and visceral fat reduction for the population of all adults.
Cause and effect cannot be established, but there is a convincing evidence of an association between brisk walking and visceral fat reduction for the population of all adults who walk briskly.
A guidance counselor sends a survey through email to all 612 Seniors at a school. The survey asks several questions about students’ plans for the next year. Based on the responses from 247 students, the counselor concludes that 89% of Seniors at this school plan to go to college. What type of bias is present in this survey?
Nonresponse bias
Response bias
Selection bias
Measurement bias
Is the sample result of 89% higher or lower than the true percent of Seniors at this school who plan to go to college?
The sample result is likely higher than the true percent because students planning to go to college may be more likely to respond.
The sample result is likely lower than the true percent because students not planning to go to college may be more likely to respond.
The sample result is exactly equal to the true percent because all students responded.
The sample result is unrelated to the true percent because the survey was sent by email.
A local election official wants to estimate the percent of registered voters who plan to vote. Which of the following best describes a process for selecting a systematic random sample?
Select every nth voter from the list after randomly choosing a starting point.
Survey only the first 100 voters on the list.
Ask voters to volunteer to participate in the survey.
Select voters based on their last names alphabetically.
What sampling method could account for this concern?
Stratified sampling
Simple random sampling
Convenience sampling
Snowball sampling
The study described in the Journal of the National Cancer Institute, which followed subjects over 32 years to observe the association between alcohol consumption and lung cancer, is an example of which type of study?
Observational study
Randomized controlled trial
Laboratory experiment
Clinical trial
Identify the explanatory and response variables in the study.
Explanatory variable: Alcohol consumption Response variable: Development of lung cancer
Explanatory variable: Development of lung cancer Response variable: Alcohol consumption
Explanatory variable: Smoking Response variable: Alcohol consumption
Explanatory variable: Age Response variable: Smoking
Smoking is a confounding variable in this study because:
it is related to both the exposure and the outcome, potentially distorting the true relationship.
it is only related to the outcome, not the exposure.
it is unrelated to either the exposure or the outcome.
it is a result of the exposure, not a separate variable.
The experimental units in the recent experiment in Norway involving virtual reality goggles and coffee bean acidity ratings are:
the 142 volunteers
the coffee beans
the virtual reality goggles
the acidity scale
The following are treatments.
Medications, therapy, surgery, and lifestyle changes
Ignoring symptoms, avoiding doctors, self-diagnosis, and procrastination
Only herbal remedies, no medical intervention, and isolation
Skipping treatment, relying on luck, and avoiding care
c. Identify the response variable.
The response variable is the outcome being measured.
The response variable is the variable being manipulated.
The response variable is always a constant.
The response variable is the control group.
Which of the following is an appropriate method the researcher could have used to randomly assign the treatments in the experiment with 142 volunteers?
Assign each volunteer a number and use a random number generator to allocate them to one of the two groups.
Let volunteers choose which group they want to join.
Assign volunteers to groups based on the order they arrive.
Group volunteers by their preference for New York City or farm images.
Suppose the researchers found that participants who viewed images of the farm rated the coffee to be more acidic and the result was statistically significant. Would it be valid to claim that the farm images caused the acidic rating to increase?
Yes, because the experiment used random assignment, allowing for causal conclusions.
No, because random assignment does not allow for causal conclusions.
No, because statistical significance does not imply causation.
Yes, because the sample size was large enough to ensure causality.
