,You passed this Milestone
27 questions were answered correctly.
2 questions were answered incorrectly.
1
Which of these random samples represents a representative sample
of the number of students who enjoy science class?
•
30 students in the lunchroom
•
30 students who participated in the science fair
•
30 students who failed science class last year
•
30 students who received high grades in their science class last semester
RATIONALE
For a sample to be representative it needs to look like the entire set of interest. By
choosing students in the lunchroom, they are drawing upon all students in the school
and not an unrepresentative one.
CONCEPT
Random & Probability Sampling
2
Aaron has designed a trial to test a new energy drink. Fifty individuals in the
treatment group try the new energy drink every day for two weeks, and they
describe a moderate increase in their energy levels. Fifty individuals in the
control group drink sugar water every day for two weeks, and they describe
a significant increase in their energy levels.
What has Aaron observed?
•
A sampling error
•
The margin of error
•
A confounding variable
, •
The placebo effect
RATIONALE
Since no treatment was given to these participants in the control group and they
reported an effect, this is what we refer to as the placebo effect.
CONCEPT
Placebo
3
A trainer is studying the effects of vitamin D on his athletes. He has realized
that there are many potential confounding factors, such as gender and age.
To limit the effect of these confounding variables, he decided to first group
two athletes together based on these variables (for example, two 21-year-old
males). Then he randomly assigned one person to receive the vitamin D and
the other to receive a sugar pill.
What type of experimental design does this situation demonstrate?
•
Randomized Block Design
•
Completely Randomized Design
•
Simple Random Design
•
Matched-Pair Design
RATIONALE
By matching on age and gender this is called a matched-pair design.
CONCEPT
Matched-Pair Design
4
The blood bank at a hospital has 1,200 units of blood, out of which 37% units
are of blood group B+. A clinical researcher randomly selects 300 units of
blood and finds that 33% of those are of blood group B+. To test his result,
he randomly selects 200 units of blood and finds that 40% of those are of
blood group B+.
27 questions were answered correctly.
2 questions were answered incorrectly.
1
Which of these random samples represents a representative sample
of the number of students who enjoy science class?
•
30 students in the lunchroom
•
30 students who participated in the science fair
•
30 students who failed science class last year
•
30 students who received high grades in their science class last semester
RATIONALE
For a sample to be representative it needs to look like the entire set of interest. By
choosing students in the lunchroom, they are drawing upon all students in the school
and not an unrepresentative one.
CONCEPT
Random & Probability Sampling
2
Aaron has designed a trial to test a new energy drink. Fifty individuals in the
treatment group try the new energy drink every day for two weeks, and they
describe a moderate increase in their energy levels. Fifty individuals in the
control group drink sugar water every day for two weeks, and they describe
a significant increase in their energy levels.
What has Aaron observed?
•
A sampling error
•
The margin of error
•
A confounding variable
, •
The placebo effect
RATIONALE
Since no treatment was given to these participants in the control group and they
reported an effect, this is what we refer to as the placebo effect.
CONCEPT
Placebo
3
A trainer is studying the effects of vitamin D on his athletes. He has realized
that there are many potential confounding factors, such as gender and age.
To limit the effect of these confounding variables, he decided to first group
two athletes together based on these variables (for example, two 21-year-old
males). Then he randomly assigned one person to receive the vitamin D and
the other to receive a sugar pill.
What type of experimental design does this situation demonstrate?
•
Randomized Block Design
•
Completely Randomized Design
•
Simple Random Design
•
Matched-Pair Design
RATIONALE
By matching on age and gender this is called a matched-pair design.
CONCEPT
Matched-Pair Design
4
The blood bank at a hospital has 1,200 units of blood, out of which 37% units
are of blood group B+. A clinical researcher randomly selects 300 units of
blood and finds that 33% of those are of blood group B+. To test his result,
he randomly selects 200 units of blood and finds that 40% of those are of
blood group B+.
