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Chapter 3 Quiz Lessons 3.5-3.9

Last updated over 1 year ago
14 questions
Note from the author:
This is an individual quiz to be done on your own, but with open notes.
This is an individual quiz to be done on your own, but with open notes.
Required
1

Does talking on a cell phone make people react slower when driving?
Sixty volunteers agree to have their reaction times tested in a driving simulator.
Thirty of the drivers were randomly assigned to talk on the phone during the simulation, while the other drivers did not talk on the phone.
During the simulation, a surprise event occurred which required each subject to step on the brake.
The time it took them to react is recorded.
The mean response time of those talking on the phone was 4.2 seconds.
The mean response time of those not talking on a cell phone was 2.9 seconds.

Describe how you would randomly assign the participants to each treatment using a random number generator.

1
Outline a completely randomized design for this experiment.
Use a half sheet of paper from Mrs. Nosal to draw the diagram.
How many treatment groups will you have? _______
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1

Use the information in #1:
Can the results of this study be generalized to all drivers?

Explain.

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1

Use the information in #1:
Calculate the difference in the mean reaction time for the two groups
(talking on a cellphone – not talking on a cell phone).

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1

Use the information in #1:
One hundred trials of a simulation were performed to see what differences in means would occur due only to chance variation in the random assignment, assuming that talking on the cell phone has no impact reaction time.
Use the results of the simulation in the dotplot below to determine if the difference in means from part (5) is statistically significant. Explain your reasoning.

Required
1

A large school district is considering moving up the start date for the school year by two weeks. In order to determine if families would support this, surveys were mailed out to 1000 parents/guardians in the district.
The School Board received 492 responses from the survey, 72% of which supported the proposal.

The survey said,
“We believe that starting school two weeks earlier will be beneficial to the students in our District. Would you support moving up the start date for the school year by two weeks?”

Describe a potential source of bias in the wording of the survey.

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1

Using information in #6:
Due to the bias described in #7, is the sample proportion of 72% likely greater than or less than the actual proportion of families who support the proposal?

Explain.

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1

Using information in #6:
Less than half of those sent the letter returned a response.

What type of bias is this? Why does this cause bias?

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1

Researchers want to test if a new medicine will help people who have trouble falling asleep. To determine if the medicine works, they give it to 100 volunteers who report having trouble sleeping.
After using the medicine for one week, the volunteers will report back on how the medication worked.
Explain how a control group and a placebo could have been used and why that is important.

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1

3.6:
In a long-term study, researchers collected information about the diets of participants and whether or not they developed the eye condition called age-related macular degeneration (AMD).
People who ate lots of green leafy vegetables, which are high in lutein and zeaxanthin, had a lower risk of AMD.
Based on this study, is it reasonable to conclude that eating green leafy vegetables causes a reduction in the risk of AMD?
What kind of randomization is necessary? Explain.

Required
1

3.6:
Elementary schools in rural India are usually small, with a single teacher. The teachers often fail to show up for work.
Here is an idea for improving attendance:
Offer the teacher better pay for good attendance. Give the teacher a digital camera with a tamper-proof time and date stamp, and ask a student to take a photo of the teacher and class at the beginning and end of the day to verify attendance. Will this work?

Researchers obtained permission to use 120 rural schools in Rajasthan for an experiment to find out.
Explain why it is necessary to include a control group that doesn’t get a financial incentive.

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1

3.6
In a series of experiments, subjects were randomly assigned to receive a flu vaccine or a placebo. In addition to recording whether or not subjects contracted the flu, researchers also recorded whether or not subjects suffered from “major adverse cardiovascular events” such as heart attacks. The subjects that received the flu vaccine were less likely to have a cardiovascular event.
Could blinding be used in this experiment? Explain. Why is blinding an important consideration in this experiment?

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1

Randomization:
Explain why random assignment is important in an experiment.

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1

Randomization:
Explain why random samples are important for surveys and observational studies.