Question

Agave is a plant that grows in Mexico and the southwestern U.S. Researchers at Penn State University conducted a study to see if a syrup made from the Agave nectar was effective at relieving cough in children. In this study the researchers recruited 80 children who went to an outpatient pediatric practice with a cough. The researchers randomly assigned the children to one of two groups (40 to each). One group received a grape flavored agave nectar and the other group received a placebo in the form of grape flavored water, which tasted identical.

The parents of the children were then asked to complete a survey on how frequently the child coughed that night. The parents were aware of whether the child received the agave or the placebo, but were instructed not to provide any information about this to their children. The researchers found that there was no statistically significant difference between the agave and placebo groups.

Question 29:

Identify the:
(1) experimental design,
(2) subjects,
(3) explanatory variable, and
(4) response variable.

Question 30- This is a single blind study. Describe how to modify to be double blinded.

Question 31: One of the researchers was concerned that younger children might respond differently to the cough syrup, so they propose an alternative design, wherein the children are split according to age. Since the 80 children in the study were from ages 4 to 12, they decided to make 2 groups, ages 4-8 and 8-12.It was found that 36 children were in the 4-8 age group, and the rest (44 children) were in the 8-12 age group. For age group 4-8,18 children were randomly assigned to agave nectar and 18 to the grape flavored water. Similar random assignment was made for age group 8-12.

Which of the following describes the design of this experiment?

Select one:

a. Stratified random design.

b. Randomized block design.

c. Simple random design.

d. Cluster design.

Answer 1

29)

1)experimental design :single blinded experimental design

2)subjects:  80 children who went to an outpatient pediatric practice with a cough

3)  explanatory variable :type of treatment: agave nectar or placebo

4)  response variable: number of times  child coughed that night

30)

we should hide the information whether the child received the agave or the placebo to make it double blind

31)

b. Randomized block design.