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Planning Assignment Worksheet & Grading

Developing a Hypothesis

Decide on an experiment that you would like to do and write a hypothesis that states the predicted outcome of your experiment. Remember: This should be something that you can alternate 1-minute without stimulus and 1-minute with stimulus. There are examples later in this document.

Hypothesis:

What is your independent variable (what will you study/manipulate)?

Independent variable:

What is your dependent variable (which data will you measure)?

Dependent variable:

Reflex Loop for the Hypothesis

What are the body processes that will stimulate the response you predicted? Fill in the reflex loop. There are examples later in this document.

· Stimulus:

· Receptor/Sensor:

· Input/Afferent pathway:

· Integrating center:

· Output/Efferent pathway:

· Effector/target:

· Predicted response:

Rationale for the Hypothesis

Your hypothesis is based on some prior knowledge or experience. A rationale is the reasoning behind your predicted result, based on what we know about the physiology of the body. The change you predict is the response of the body to the independent variable you will manipulate. This is a physiological response that acts through a reflex loop. There are examples later in this document. In your answer, include:

(1) which previous knowledge or experience led you to this prediction? (for the last experiment of the semester, you need to include the previous experiment you are improving or expanding)

(2) how does your manipulated variable connect to the physiological mechanism you think will lead to your predicted response? (hint: include some parts of a reflex loop)

(3) include in-text and list APA citations for the physiological mechanism (see posted APA guide)

Rationale:

Instructions for Developing a Hypothesis

To develop a good hypothesis, determine:

· what you want to change. This is an independent variable. This is the stimulus you are testing.

· what you want to measure. You expect you will be able to measure a response to the stimulus you test. What you are measuring is the dependent variable. It is dependent on the stimulus you are testing.

· how you think the measurement will change. Be specific. Do not say it will change, rather predict whether it will increase or decrease. You could also predict how much it will increase or decrease.

The hypothesis can then be developed in one of the following formats. These are examples based on the effect of running on heart rate. (For your experiment, do not include exercise in your hypothesis since we already know that exercise increases heart rate).

· If (stimulus) then (how you think the response/measurement will change).

· If a subject runs for five minutes (stimulus), his/her heart rate will increase (the response/measurement is heart rate, and you expect it will increase).

· The statement above could also be written without the if/then: The (stimulus) will (how you think the response/measurement will change).

· Running for five minutes (stimulus) will increase heart rate (how you think the response/measurement will change).

· This could be written another way. The (how you think the response/measurement will change) when (stimulus).

· The heart rate will increase (how you think the measurement will change) when running for five minutes (stimulus).

Planning Assignment Example

Hypothesis: If a subject runs for five minutes, heart rate will increase.

Rationale: When I run I become out of breath. As we use more oxygen to make ATP, we make more carbon dioxide which stimulates our sympathetic nervous system to cardiac myocytes to increase heart rate. This will help to pump more oxygen to skeletal muscle cells (Silverthorn, 2012).

Silverthorn, D.U. (2012). Human Physiology: An Integrated Approach. Pearson: San Francisco.

Reflex Loop:

· Stimulus: The physical activity of running will increase blood CO2.

· Receptor: chemoreceptor in the cells of the aorta

· Input/Afferent Pathway: sensory neuron from this receptor to the brain

· Integrating Center: brain

· Output/Efferent Pathway: sympathetic neurons release neurotransmitter (norepinephrine)

· Target/Effector Cells: beta one receptors on autorhythmic cells in the SA node of the heart

· Predicted Response: increased heart rate

Grading Criteria for Planning Assignment

Hypothesis (1.75 points)	Yes (	No (
Written as a statement making a prediction	0.25	0
Includes manipulation of one specific independent variable	0.25	0
Based on the reading of the correct laboratory (e.g., HR) and instructions	0.25	0
Includes correct measurements/dependent variables (e.g., HR)	0.25	0
Makes specific prediction about how dependent variable will change	0.25	0
Creative hypothesis that will test something not already known	0.25	0
Can be tested by students in this course	0.25	0

Variables (0.5 points)	Yes (	No (
Correctly identified independent variable	0.25	0
Correctly identified dependent variable	0.25	0

Reflex Loop (1.75 points)	Yes (	Sort of…	No(
Identify a correct or well-reasoned Stimulus; matches hypothesis	0.25	0.15	0
Identify a correct or well-reasoned Receptor/Sensor	0.25	0.15	0
Identify a correct or well-reasoned Input/Afferent Pathway	0.25	0.15	0
Identify a correct or well-reasoned Integrating Center	0.25	0.15	0
Identify a correct or well-reasoned Output/Efferent Pathway	0.25	0.15	0
Identify a correct or well-reasoned Target/Effector	0.25	0.15	0
Identify a correct or well-reasoned Response; matches hypothesis	0.25	0.15	0

Rationale (0.75 points)	Yes (	Sort of…	No(
(1) Previous knowledge or life experience is described and connected	0.25	0.15	0
(2) Connects manipulated variable to stimulation of predicted response	0.25	0.15	0
(3) Includes in-text & list citations using APA format	0.25	0.15	0

Spelling/Grammar (0.25 points)	Yes (	No (
Minimal spelling or grammatical errors	0.25	0

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