Deck 11: Experiments and Observational Studies

Question 1

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test.In a study, there are
Four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods
(method A, method B, and method C).The number of students participating in the study is 258.Students are randomly assigned to a teaching method and teacher.Identify the response
Variable measured.

A)Teaching method
B)The education researcher
C)Score on reading test
D)Method A, method B, method C

Answer 1

C

Question 2

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test.In a study, there are
Four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods
(method A, method B, and method C).The number of students participating in the study is 258.Students are randomly assigned to a teaching method and teacher.Identify the factor(s)
In the experiment.

A)The education researcher
B)Teaching method and teacher
C)Juliana, Felix, Sonia, and Helen
D)Method A, method B, method C
E)Score on reading test

Answer 2

B

Question 3

A survey of online consumers asked respondents to indicate how much money they spent for online purchases during the most recent Christmas holiday season.These data were analyzed
To see if gender and income level influence the amount consumers spend online for holiday
Shopping.Which of the following statements is true?
I)This is an experimental study.
II)This is a randomized block design.
III)This is an observational study.

A)I only
B)II only
C)III only
D)Both I and III
E)Both II and III

Answer 3

C

Question 4

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low
Dosage of an experimental drug, the second group received a high dosage of the drug, and the
Third group received a placebo.The diastolic blood pressure of each participant was
Measured at the beginning and at the end of the period and the change in blood pressure was
Recorded.Identify the response variable measured.

A)Change in diastolic blood pressure
B)The treatment received (placebo, low dosage, high dosage.
C)The participants in the experiment
D)The dosage of the drug

Question 5

It was discovered that a larger proportion of children who slept with nightlights later developed nearsightedness, compared to children who did not sleep with nightlights.The
Headlines read, "Leaving a light on for you children causes nearsightedness!" Later it was
Pointed out that nearsighted people have more trouble seeing in the dark and are more likely
To leave lights on at night for their kids.And those same nearsighted parents are likely to
Have nearsighted kids.This is an example of

A)a randomized block design.
B)a control group.
C)bias.
D)a placebo.
E)a lurking variable.

Question 6

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test.In a study, there are
Two different teachers (Juliana and Felix) and three different teaching methods (method A,
Method B, and method C).The number of students participating in the study is 258.Students
Are randomly assigned to a teaching method and teacher.Identify the treatments.

A)Juliana and method A, Juliana and method B, Juliana and method C, Felix and method A, Felix and method B, Felix and method C
B)Juliana, Felix, Sonia, and Helen
C)Method A, method B, method C
D)The education researcher
E)Teaching method and teacher

Question 7

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low
Dosage of an experimental drug, the second group received a high dosage of the drug, and the
Third group received a placebo.The diastolic blood pressure of each participant was
Measured at the beginning and at the end of the period and the change in blood pressure was
Recorded.Identify the factor in the experiment.

A)Diastolic blood pressure
B)The dosage of the drug
C)The participants in the experiment
D)The experimental drug
E)The one-month period

Question 8

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low
Dosage of an experimental drug, the second group received a high dosage of the experimental
Drug, and the third group received a placebo.The diastolic blood pressure of each participant
Was measured at the beginning and at the end of the period and the change in blood pressure
Was recorded.Identify the treatments.

A)The experimental drug
B)The one-month period
C)Placebo, low dosage of drug, high dosage of drug
D)Low dosage of drug, high dosage of drug

Question 9

Which is not a critical part of designing a good experiment?

A)Control of known sources of variability.
B)Replication of the on a sufficient number of subjects.
C)Random selection of subjects.
D)Random assignment of subjects to treatments.
E)All of these are important.

Question 10

Which is true about randomized experiments? I.Randomization reduces the effects of confounding variables.
II)Random assignment of treatments allows results to be generalized to the larger
Population.
III)Blocking can be used to reduce the within-treatment variability.

A)I only
B)II only
C)III only
D)I and III
E)I, II, and III

Question 11

An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test.In a study, there are
Four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods
(method A, method B, and method C).The number of students participating in the study is 258.Students are randomly assigned to a teaching method and teacher.Identify the levels of
The factor "teaching method."

A)Teaching method and teacher
B)Juliana, Felix, Sonia, and Helen
C)The education researcher
D)Score on reading test
E)Method A, method B, method C

Question 12

A company has tried to improve the effectiveness of its dishwashing detergent and wants to see if it works better than the original formula.They use 6 identical new dishwashers and
Load them identically with dirty dishes.Three packs of each of the two types of detergent are
Used, and they are randomly assigned to one of the six dishwashers.After the load is run,
They rate each load for overall cleanliness.Which of the following is true?

A)The response variable is the type of detergent.
B)The explanatory variable is the different dishwashers.
C)Because each brand is used in three dishwashers, replication is used properly.
D)Blinding is impossible in this experiment because they must be able to see the dishes.
E)A control group with no detergent at all is needed.

Question 13

Quality control engineers fire tiles made with this new material at three different temperature settings (1500°F, 1800°F and 2200°F) and for four different times (2 hours, 6 hours, 10 hours
And 12 hours) to determine the optimal parameter settings for firing that will result in tiles
With high flexural strength.The response variable in this experiment is

A)firing temperature.
B)the new material.
C)tiles.
D)flexural strength.
E)firing time.

Question 14

Do energy snack bars improve afternoon alertness? 100 factory workers were randomly assigned to two groups.One group ate energy snack bars at lunch and the other group ate
Placebo snack bars.At the afternoon break (approximately 1-1/2 hour after lunch), a
Significant increase in alertness was observed.Later analysis of the experiment results
Showed 87% of the participants exhibiting increased alertness were from the group which ate
Energy snack bars.

A)Double blind
B)Single blind, only participant is blinded
C)Single blind, only evaluator is blinded
D)Neither

Question 15

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low
Dosage of an experimental drug, the second group received a high dosage of the drug, and the
Third group received a placebo.The diastolic blood pressure of each participant was
Measured at the beginning and at the end of the period and the change in blood pressure was
Recorded.Identify the levels of the factor.

A)Placebo, low dosage, high dosage
B)Diastolic blood pressure at the start, diastolic blood pressure at the end
C)The experimental drug
D)High blood pressure, low blood pressure
E)The one-month period

Question 16

The experiment is run once for each combination of brand of AAA batteries and device (TV remote, hand-held game, flashlight and digital camera).The twelve runs are ordered
Randomly.The time (in minutes) that each battery lasts under continuous usage is recorded.
Which of the following statements is true about this design?

A)The devices serve as blocks to account for the variability between the lengths of time batteries last in different devices.
B)This is a completely randomized design in one factor.
C)The interaction effect between brand of battery and type of device is significant.
D)This is an observational study.
E)This is a retrospective study.

Question 17

An advocacy group is interested in determining if gender (1 = Female, 2 = Male) affects executive level salaries.They take a random sample of executives in three different
Industries: (1 = Consumer Goods, 2 = Financial, 3 = Health Care).Salary data are collected.
Which of the following statements is true?
I)This is an experimental study.
II)This is an observational study.
III)This is a randomized block design.

A)I only
B)II only
C)III only
D)Both I and III
E)Both II and III