Question

Can you write In your lab notebook, design a controlled experiment to test the hypothesis "A low salt diet reduces blood pressure in mice." You have access to: 300 mice, BP-Reducer (a blood pressure medication known to reduce blood pressure in mice), Mouse-Chow (a regular mouse diet), Reduced Salt Mouse-Chow (a low-salt mouse diet that is exactly the same as Mouse-Chow except that it has less salt). You have a large group of assistants that staff the mouse facility around the clock, 7 days a week, and are experts at caring for and taking blood pressure readings of mice. From previous observations in humans and other animals, you expect it will take at least 3 weeks for a change in diet to affect blood pressure.

Describe your experimental design. Be sure to identify your:
1. Independent variable
2. Dependent variable
3. At least 3 variables you will need to control
4. Your experimental group
5. Your negative control group
6. Your positive control group

Answer 1

To test the hypothesis that a low salt diet reduces blood pressure in mice, the independent variable is the type of diet, and the dependent variable is the blood pressure. Controlled variables would include the genetic background of the mice, their housing conditions, and handling during measurements. The experimental design includes an experimental group fed Reduced Salt Mouse-Chow, a negative control group on regular Mouse-Chow, and a positive control group given BP-Reducer medication.

Step-by-step explanation:

To design a controlled experiment to test the hypothesis "A low salt diet reduces blood pressure in mice," we first need to identify different components of the experimental design. These include:

• Independent variable: This is the variable you manipulate. In this case, it's the type of diet — either the regular Mouse-Chow or the Reduced Salt Mouse-Chow.
• Dependent variable: The outcome you're measuring, which is blood pressure in mice.
• Variables that need to be controlled include:
  1. The strain or genetic background of the mice, to avoid genetic variations affecting the result.
  2. Mouse housing conditions, ensuring they are the same for all groups to prevent environmental factors from influencing blood pressure.
  3. Handling of mice during blood pressure reading, so the stress of handling does not impact blood pressure measurements.
• Experimental group: A group of mice that will receive the Reduced Salt Mouse-Chow.
• Negative control group: A group of mice that will receive the regular Mouse-Chow, which is not expected to change blood pressure.
• Positive control group: A group of mice that will receive the BP-Reducer medication. This group confirms that the experimental setup can detect a reduction in blood pressure.

You would randomly assign the 300 mice into these three groups and ensure all other conditions are kept constant across the groups. After at least 3 weeks, compare the blood pressure measurements from before the diet change to after, using proper statistical analysis to determine if there is a significant difference in blood pressure between the groups.