Data Collection - AP Statistics
Card 1 of 192
A study is trying to determine if a particular medication (Y) is effective in weight loss. Patients participating in the study were randomly assigned to groups A, B, C, D, or E. Group A will receive one dose of Y, Group B will receive two doses of Y, Group C will receive three doses of Y, Group D will receive four doses of Y, and Group E will serve as the control group.
Which group will be receiving the placebo (a sugar pill)?
A study is trying to determine if a particular medication (Y) is effective in weight loss. Patients participating in the study were randomly assigned to groups A, B, C, D, or E. Group A will receive one dose of Y, Group B will receive two doses of Y, Group C will receive three doses of Y, Group D will receive four doses of Y, and Group E will serve as the control group.
Which group will be receiving the placebo (a sugar pill)?
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The control group in an experiment typically receives placebo treatments (in this case - Group E). Since all of the other groups are receiving at least one dose of the medication, they are considered to be experimental groups.
The control group in an experiment typically receives placebo treatments (in this case - Group E). Since all of the other groups are receiving at least one dose of the medication, they are considered to be experimental groups.
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To test if vitamin C actually makes people feel better, a vitamin company decides to run a 5-day study where they give one group of 100 sick participants vitamin C pills and another group of 100 sick people placebo pills, and monitored another group of 100 sick people who took no pills.
At the end of the 5-day experiment, 90 participants in the vitamin C group reported feeling better. 30 participants in the no-pill group felt better after the 5-day period. Interestingly, 50 participants in the placebo group felt better after the 5-day period.
What could explain these numbers?
To test if vitamin C actually makes people feel better, a vitamin company decides to run a 5-day study where they give one group of 100 sick participants vitamin C pills and another group of 100 sick people placebo pills, and monitored another group of 100 sick people who took no pills.
At the end of the 5-day experiment, 90 participants in the vitamin C group reported feeling better. 30 participants in the no-pill group felt better after the 5-day period. Interestingly, 50 participants in the placebo group felt better after the 5-day period.
What could explain these numbers?
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The placebo effect is when effects are seen in a group of people who did not actually receive a treatment.
In the vitamin C group, 90 participants felt better.
Naturally (no-pill), 30 participants felt better.
With the placebo, 50 participants felt better. Since more people felt better with the placebo than with no treatment at all, it appears that some percentage of people believed that they would feel better with a pill and actually began to feel better due to the placebo effect.
The placebo effect is when effects are seen in a group of people who did not actually receive a treatment.
In the vitamin C group, 90 participants felt better.
Naturally (no-pill), 30 participants felt better.
With the placebo, 50 participants felt better. Since more people felt better with the placebo than with no treatment at all, it appears that some percentage of people believed that they would feel better with a pill and actually began to feel better due to the placebo effect.
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Let us suppose a company wants to evaluate whether a new medical device works better than current devices. It conducts a small experiment to assess the effectiveness of the new device. To conduct the experiment, the company randomly assigns one group to the new medical device, which requires users to stay well hydrated, and the other group to the old device.
How should we control for confounding variables?
Let us suppose a company wants to evaluate whether a new medical device works better than current devices. It conducts a small experiment to assess the effectiveness of the new device. To conduct the experiment, the company randomly assigns one group to the new medical device, which requires users to stay well hydrated, and the other group to the old device.
How should we control for confounding variables?
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When comparing the effectiveness of a treatment, one should try to ensure that only the treatment varies across groups. In this case, the new device is compared to an old device. However, the new device also requires that users stay well hydrated. If we observe any positive effects from the new device, we won't know whether the new device is effective, or if merely staying well hydrated is actually what is effective. To rule out this confounding variable, we should also ask the group using the old machine condition to stay hydrated as well.
When comparing the effectiveness of a treatment, one should try to ensure that only the treatment varies across groups. In this case, the new device is compared to an old device. However, the new device also requires that users stay well hydrated. If we observe any positive effects from the new device, we won't know whether the new device is effective, or if merely staying well hydrated is actually what is effective. To rule out this confounding variable, we should also ask the group using the old machine condition to stay hydrated as well.
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An experiment was done by medical researchers to determine the association between drinking caffeine and severity of lung cancer. Results showed that there was a high association between the two variables. Which of the following could be a potential confounding variable in the experiment?
An experiment was done by medical researchers to determine the association between drinking caffeine and severity of lung cancer. Results showed that there was a high association between the two variables. Which of the following could be a potential confounding variable in the experiment?
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A confounding variable is one that could potentially have an effect on both the independent and dependent variables in a study. In this case, it is possible that there is an association between smoking and caffeine as well as smoking and lung cancer.
A confounding variable is one that could potentially have an effect on both the independent and dependent variables in a study. In this case, it is possible that there is an association between smoking and caffeine as well as smoking and lung cancer.
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A study finds that caffeine intake has a strong positive correlation with grades for college students. In other words, on average, the more caffeine intake a student has, the higher a grade the student gets.
Which of the following could potentially be a confounding variable in this experiment?
A study finds that caffeine intake has a strong positive correlation with grades for college students. In other words, on average, the more caffeine intake a student has, the higher a grade the student gets.
Which of the following could potentially be a confounding variable in this experiment?
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The only confounding variable in this experiment is the amount of sleep that each student gets. A confounding variable is one that has an impact on both the dependent and independent variable. It is possible that the amount of sleep a student gets is related to caffeine intake, which in turn affects the grade a student receives on a test or assignment.
The only confounding variable in this experiment is the amount of sleep that each student gets. A confounding variable is one that has an impact on both the dependent and independent variable. It is possible that the amount of sleep a student gets is related to caffeine intake, which in turn affects the grade a student receives on a test or assignment.
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An experiment testing the effects of caffeine on endurance performance in athletes assigns caffeine to a randomly selected group of athletes and has them exercise. Another trial was conducted in which the same group exercised without anything given to them to take. The results did not match the expected results. What should be done to improve this experiment?
An experiment testing the effects of caffeine on endurance performance in athletes assigns caffeine to a randomly selected group of athletes and has them exercise. Another trial was conducted in which the same group exercised without anything given to them to take. The results did not match the expected results. What should be done to improve this experiment?
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The placebo effect can potentially be a confounding variable. By knowingly taking a substance, participants may feel more energenized. By administering the same substance both trials, with the only thing changed being caffeine content, this corrects for this possible confounding variable.
The placebo effect can potentially be a confounding variable. By knowingly taking a substance, participants may feel more energenized. By administering the same substance both trials, with the only thing changed being caffeine content, this corrects for this possible confounding variable.
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A small local umbrella company is trying to test the effectiveness of their umbrellas by looking at how many umbrellas they sell each year.
In 2014, the company sold 2,000 umbrellas.
In 2015, they sold 1,500 umbrellas.
They assume that their umbrellas are less effective which is why sales decreased.
However, there could be many confounding factors. Which of the following is NOT a possible confounding factor?
A small local umbrella company is trying to test the effectiveness of their umbrellas by looking at how many umbrellas they sell each year.
In 2014, the company sold 2,000 umbrellas.
In 2015, they sold 1,500 umbrellas.
They assume that their umbrellas are less effective which is why sales decreased.
However, there could be many confounding factors. Which of the following is NOT a possible confounding factor?
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Any of these answers could explain why umbrella sales dropped. You cannot assume any specific cause explains a change in data like this-- further experimentation should be done rather than assuming cause and effect.
Any of these answers could explain why umbrella sales dropped. You cannot assume any specific cause explains a change in data like this-- further experimentation should be done rather than assuming cause and effect.
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Alpha Corporation developed a new pill to treat elevated glucose levels. They want to test the efficiency of the pill to lower glucose levels by gathering a sample of people with high glucose and giving them either:
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A daily dose of their new pill ("Experimental Group")
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A daily placebo pill that looks the same but does not do anything ("Placebo Group")
How can they make this a "Blind Study"?
Alpha Corporation developed a new pill to treat elevated glucose levels. They want to test the efficiency of the pill to lower glucose levels by gathering a sample of people with high glucose and giving them either:
-
A daily dose of their new pill ("Experimental Group")
-
A daily placebo pill that looks the same but does not do anything ("Placebo Group")
How can they make this a "Blind Study"?
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A blind experiment is one in which the participant does not know which experimental group they are in-- which is accomplished by not letting them know if they are in the Experimental or Placebo group.
A blind experiment is one in which the participant does not know which experimental group they are in-- which is accomplished by not letting them know if they are in the Experimental or Placebo group.
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A study is attempting to test various brands of cola against each other. Which of these would not be a measure that could be used to help create a double blind test?
A study is attempting to test various brands of cola against each other. Which of these would not be a measure that could be used to help create a double blind test?
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Remember that a double blind experiment means that neither the subject nor the person conducting the experiment knows the identity of the various treatments until the test is over, so as to minimize bias.
Therefore of the options,
serving the samples to the taster in their usual containers, is the one which would not help create a double blind test.
Remember that a double blind experiment means that neither the subject nor the person conducting the experiment knows the identity of the various treatments until the test is over, so as to minimize bias.
Therefore of the options,
serving the samples to the taster in their usual containers, is the one which would not help create a double blind test.
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Which of the following is an example of a double blind experiment?
Which of the following is an example of a double blind experiment?
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A double blind experiment requires that both researchers and test subjects are unaware of who is receiving the treatment and who is receiving the placebo. If only one group is unaware, it is a single blind experiment. If both groups are aware, the experiment is not blinded.
A double blind experiment requires that both researchers and test subjects are unaware of who is receiving the treatment and who is receiving the placebo. If only one group is unaware, it is a single blind experiment. If both groups are aware, the experiment is not blinded.
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Which of the following is an example of a single-blind experiment?
Which of the following is an example of a single-blind experiment?
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In a single-blind experiment, one group (either the researchers or the test subjects) must be blinded while the other group is aware of who is receiving a placebo and who is receiving a therapy.
The following two examples are correct:
-An experiment in which the test subjects are aware of who is receiving a placebo and who is receiving a therapy, but the researchers are unaware.
-An experiment in which the researchers are aware of who is receiving a placebo and who is receiving a therapy, but the test subjects are unaware.
In a single-blind experiment, one group (either the researchers or the test subjects) must be blinded while the other group is aware of who is receiving a placebo and who is receiving a therapy.
The following two examples are correct:
-An experiment in which the test subjects are aware of who is receiving a placebo and who is receiving a therapy, but the researchers are unaware.
-An experiment in which the researchers are aware of who is receiving a placebo and who is receiving a therapy, but the test subjects are unaware.
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A drug company wants to test a new pill that should make people's nails grow twice as quickly as normal. How can they make the study a blind study?
A drug company wants to test a new pill that should make people's nails grow twice as quickly as normal. How can they make the study a blind study?
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In order for a study to be "blind," the participants can't know which group they are sorted into. For a study to be double-blind, which is even better, the researchers should also be blind to which group participants are in until the study is completed.
In order for a study to be "blind," the participants can't know which group they are sorted into. For a study to be double-blind, which is even better, the researchers should also be blind to which group participants are in until the study is completed.
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You and your classmate want to test the effect of food coloring on plant color. One of the groups in the experiment receives dye-free water. Which group is this?
You and your classmate want to test the effect of food coloring on plant color. One of the groups in the experiment receives dye-free water. Which group is this?
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The control group receives no treatment.
The experimental group receives the treatment of the independent variable.
Because the flowers getting no dye do not receive the treatment, it is the control group.
The control group receives no treatment.
The experimental group receives the treatment of the independent variable.
Because the flowers getting no dye do not receive the treatment, it is the control group.
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You and your friend want to test the effect of different brands of fertilizer on sunflower height.
One group receives no fertilizer during the course of the experiment.
Which group is this?
You and your friend want to test the effect of different brands of fertilizer on sunflower height.
One group receives no fertilizer during the course of the experiment.
Which group is this?
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The control group receives no treatment.
The experimental group receives the treatment of the independent variable.
Because the sunflowers getting no fertilizer do not receive the treatment, it is the control group.
The control group receives no treatment.
The experimental group receives the treatment of the independent variable.
Because the sunflowers getting no fertilizer do not receive the treatment, it is the control group.
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A drug company wants to test whether its medication reduces cancer risk. Assuming the company conducts an experiment in which participants are randomly assigned to treatment and control groups, what would the appropriate control group look like?
A drug company wants to test whether its medication reduces cancer risk. Assuming the company conducts an experiment in which participants are randomly assigned to treatment and control groups, what would the appropriate control group look like?
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The only thing you want to vary across groups when you're conducting an experiment is the treatment. Since taking pills is a part of taking medication (the treatment), medical experiments often employ something called a placebo-controlled study where outcomes for those who are randomly assigned to take the medication are compared to outcomes for those who are randomly assigned to take a sugar pill. The sugar pill is expected to have no effect, so it serves as a useful baseline to compare the treatment to.
The only thing you want to vary across groups when you're conducting an experiment is the treatment. Since taking pills is a part of taking medication (the treatment), medical experiments often employ something called a placebo-controlled study where outcomes for those who are randomly assigned to take the medication are compared to outcomes for those who are randomly assigned to take a sugar pill. The sugar pill is expected to have no effect, so it serves as a useful baseline to compare the treatment to.
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In a public health study, researchers want to see how the addition of fresh produce stands in inner cities can affect the body weights of people who live within 1 mile of the stands.
The research group gathers data from several groups. Please identify which is the Control group.
In a public health study, researchers want to see how the addition of fresh produce stands in inner cities can affect the body weights of people who live within 1 mile of the stands.
The research group gathers data from several groups. Please identify which is the Control group.
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Areas A and B are both experimental areas, where they received the treatment (the new produce stand), so comparing body weights before and after the treatment will provide valuable data.
The area of the city which did not receive the treatment (a produce stand) will provide data of how body weight may change over time naturally, without the stand, in order to compare the effects of the stands elsewhere.
The nearby town already has produce stands and provides residents with a different food environment, so it cannot act as the control group. It has different conditions than the experimental areas A and B, so comparing it to these areas will not provide helpful data in terms of the treatment's effects.
Areas A and B are both experimental areas, where they received the treatment (the new produce stand), so comparing body weights before and after the treatment will provide valuable data.
The area of the city which did not receive the treatment (a produce stand) will provide data of how body weight may change over time naturally, without the stand, in order to compare the effects of the stands elsewhere.
The nearby town already has produce stands and provides residents with a different food environment, so it cannot act as the control group. It has different conditions than the experimental areas A and B, so comparing it to these areas will not provide helpful data in terms of the treatment's effects.
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To find the percentage of households in a town who own more than one motor vehicle, a survey will ask the next 100 drivers at a popular gas station if there is more than one motor vehicle in their household. Is this survey biased and if so, what is the main type of bias?
To find the percentage of households in a town who own more than one motor vehicle, a survey will ask the next 100 drivers at a popular gas station if there is more than one motor vehicle in their household. Is this survey biased and if so, what is the main type of bias?
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Because the survey is being conducted on drivers at a gas station, people/households who do not own a motor vehicle will not be included in the survey.
Because the survey is being conducted on drivers at a gas station, people/households who do not own a motor vehicle will not be included in the survey.
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The best way to reduce variability in an unbiased sample is to .
The best way to reduce variability in an unbiased sample is to .
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Using random sampling methods alone does not reduce variability in a sample; they only reduce bias. The best way to reduce variability in an unbiased sample is to take a bigger sample—the bigger the population of the sample, the less widespread the results will be. It is important to remember that if there is bias present in a sample, a large sample population size (n value) will not be enough to overcome the bias.
Using random sampling methods alone does not reduce variability in a sample; they only reduce bias. The best way to reduce variability in an unbiased sample is to take a bigger sample—the bigger the population of the sample, the less widespread the results will be. It is important to remember that if there is bias present in a sample, a large sample population size (n value) will not be enough to overcome the bias.
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Identify the type of bias:
A radio station polls listeners on a controversial issue by talking to people who call in to the station.
Identify the type of bias:
A radio station polls listeners on a controversial issue by talking to people who call in to the station.
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Voluntary response bias usually results when those sampled are volunteers who select themselves.
Voluntary response bias can cause results to over represent those who have a strong opinion.
Voluntary response bias usually results when those sampled are volunteers who select themselves.
Voluntary response bias can cause results to over represent those who have a strong opinion.
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Identify the type of bias:
A researcher wants to know what proportion of people in the United States favor student debt reform. The researcher goes to five universities and at each asks people whether they favor student debt reform.
Identify the type of bias:
A researcher wants to know what proportion of people in the United States favor student debt reform. The researcher goes to five universities and at each asks people whether they favor student debt reform.
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This is an example of undercoverage because the researcher did not speak to people who were not affiliated with a university. Therefore the researcher did not adequately sample all members of the overall population (people in the United States).
This is an example of undercoverage because the researcher did not speak to people who were not affiliated with a university. Therefore the researcher did not adequately sample all members of the overall population (people in the United States).
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