Establishing the Purpose & Forming A Valid Hypothesis

Introduction to Research

What should the Purpose include?

The inclusion of the purpose (sometimes called the objective) of the experiment often confuses writers. The biggest misconception is that the purpose is the same as the hypothesis.

Not quite. The purpose is broader, and is a statement of what you expect to gain or learn through the experiment.

What is a Hypothesis?

A hypothesis is a tentative statement that proposes a possible explanation to some phenomenon or event.

A useful hypothesis is a testablestatement which may include a prediction.

Please note that scientific writing is more formal and is written in third person (the investigator or the researchers) rather than in first person (I or we).

How is a Hypothesis Written?

Hypotheses take four formats: a question, "Does temperature affect

fermentation?" a conditional statement, "Temperature may affect

fermentation." an “as” statement, “As temperature increases, as

production through fermentation will also increase

an “If, then” statement, "If fermentation rate is related to temperature, then increasing the temperature will increase gas production.

The format of a hypothesis includes the independent and dependent variable (what is to be manipulated and what is to be observed).

Writing A Hypothesis

a question,"Does temperature affect

fermentation?"

a conditional statement, "Temperature may affect

fermentation."

How Are Hypotheses Written?

an “as” statement, “As temperature increases,

as production through fermentation will also increase

an “If, then” statement,"If fermentation rate is relatedto temperature, then increasing the temperature will increase

gas production.

The format of a hypothesis includes the independent and dependentvariable (what is to be manipulated and what is to be observed).

How Are Hypotheses Written?

The format of a hypothesis includes the Independent variable

(what is to be manipulated) and

Dependent variable (and what is to be observed).

Are theseValid Hypotheses?

1. Chocolate may cause pimples.

2. Salt in soil may affect plant growth.

3. Plant growth may be affected by the color of the light.

4. Bacterial growth may be affected by temperature.

5. Ultra violet light may cause skin cancer.

6. Temperature may cause leaves to change color.

How could we re-write this so that it is in a BETTER

form of an Hypothesis?

Why or Why Not?

All of these are examples of hypotheses because they use the tentative word "may.".

However, their form is not particularly useful. Using the word may does not suggest how you would go about proving it.

If these statements had not been written carefully, they may not have even been hypotheses at all. For example, if we say "Trees will change color when it gets cold." we are making a prediction. Or if we write, "Ultraviolet light causes skin cancer." could be a conclusion.

One way to prevent making such easy mistakes is to formalize the form of the hypothesis.

Formalized Hypothesis

A formalized hypothesis consists of an “If…Then..” Statement and Two Variables. If the IV does this, then the DV will do that. An “as” statement may also be considered formalized. As the IV does this, then the DV will do that.”

But not all if-then statements are hypotheses. For example, "If I play the lottery, then I will get rich. This is a simple prediction.

Formalized Hypothesis

In a formalized hypothesis, a tentative relationship is stated. For example, if the frequency of winning is related to frequency of buying lottery tickets, "Then" is followed by a prediction of what will happen if you increase or decrease the frequency of buying lottery tickets.

The ultimate value of a formalized hypothesis is it forces us to think about what results we should look for in an experiment.

Practice Rewrite the first four hypotheses using the

formalized style shown earlier. Single underline the dependent variable and double underline the independent variable in the If clause of each hypothesis.

1. Chocolate may cause pimples.

2. Salt in soil may affect plant growth.

3. Plant growth may be affected by the color of the light.

4. Bacterial growth may be affected by temperature.

Why is a Rationale Statement Necessary?

A rationale statement provides a professional argument for the hypothesis you are submitting.

The rationale statement communicates the link between the expected outcome, prior knowledge, and new knowledge gained through research.

The hypothesis and rationale must enable readers to understand your professional thinking and understanding of the experiment.

Check your UNDERSTANDING

What should the Purpose include?

The inclusion of the ________ (sometimes called the objective) of the experiment often confuses writers. The biggest misconception is that the purpose is the same as the hypothesis.

Not quite. The purpose is ________, and is a statement of what you expect to ___ or learn through the experiment.

What is a Hypothesis?

A hypothesis is a ________ statement that proposes a possible explanation to some phenomenon or event.

A useful hypothesis is a _____ statement which may include a __________.

Please note that scientific writing is more ______ and is written in ____ person (the investigator or the researchers) rather than in _______ person (I or we).

How Are Hypotheses Written? Hypotheses take four formats:

a _________, "Does temperature affect fermentation?"

a __________ statement, "Temperature may affectfermentation."

an “__” statement, “As temperature increases, as production through fermentation will also increase

an “__, ____” statement, "If fermentation rate is related to temperature, then increasing the temperature will increase gas production.

The format of a hypothesis includes the ________ and __________ variable (what is to be manipulated and what is to be observed).

Formalized Hypothesis

A formalized hypothesis consists of an “__________” Statement and _______________. If the IV does this, then the DV will do that. An “as” statement may also be considered formalized. As the IV does this, then the DV will do that.”

But not all ___________ statements are hypotheses. For example, "If I play the lottery, then I will get rich. This is a simple prediction.

Formalized Hypothesis

In a formalized hypothesis, a __________ relationship is stated. For example, if the frequency of winning is _________ to frequency of buying lottery tickets, "Then" is followed by a prediction of what will happen if you increase or decrease the frequency of buying lottery tickets.

The ultimate value of a ________ hypothesis is it forces us to think about what results we should look for in an experiment.

For your PROPOSED FIRST CHOICE,Write your FORMAL HYPOTHESIS

What are your Independent Variables?

What are your constants?