1.3 Experimental Design

Question 1

What are the two steps to creating a good hypothesis?

Answer 1

1. come up with a specific reason that explains the phenomena/topic
2. write a testable statement

Question 2

True or False?
You should be as specific as possible when writing a testable statement.

Answer 2

True
Always be as specific as possible when writing a hypothesis.

Question 3

When should you use a line graph to represent a data set?

Answer 3

When the independent variable is quantified or related to time you should use a line graph.

Question 4

When should you use a bar graph to represent a data set?

Answer 4

When the independent variable is grouped (categorical).

Question 5

True or False?
There can be multiple control groups, but only one experimental group.

Answer 5

False
There can be multiple experimental groups but ONLY ONE control group.

Question 6

What does “statistically significant” mean?

Answer 6

When scientists are referring to a data set as “statistically significant” they mean that the results are most likely reliable, real, and not due to chance.

Question 7

What is the preferred template for the first part of writing a hypothesis (a specific reason that explains the phenomenon)?

Answer 7

The <phenomenon/topic> (is caused by, due to, etc.) <reason>.</reason>

Question 8

What is the preferred template for the second part of writing a hypothesis (a testable statement)?

Answer 8

If <independent> <increases/decreases>, then <dependent> will <increase/decrease>.</dependent></independent>

Question 9

Determine the independent and dependent variables of the following question:
How does stress relate to the body’s immune system?

Answer 9

Independent Variable: the amount of stress the person is subject to
Dependent Variable: the body’s reaction to a certain virus

Question 10

Write a hypothesis for the following question:
How does stress relate to the body’s immune system?

Answer 10

People with high-stress levels will be more likely to contract a certain virus, compared to those with low stress levels. This is because having chronic stress lowers your lymphocyte level. We can expose both groups to a certain virus, such as the common cold. So when the same amount of a virus is being exposed to the two groups, we can see if more people of high-stress or low-stress contract the disease.