HYPOTHESIS

A hypothesis is a tentative statement that proposes a posible explanation to some phenomenon or even. A useful hypothesis is a testable statement which may include a prediction.

A hypothesis should not be confused with a theory. Thoeries are general explanations based on a large amount of data. For example, the theory of evolution of evolution applies to all living things and is based on wide range of observations. However, there are many things about evoltion that are not fully understood such as gaps in the fosil record. Many hypotheses have been proposed and tested.

When To Use Hypothesis.

The key word is testable. That is, you will perform a test on how two variables might be related. This is when you are doing a real experiment. You are testing variables. Usually, a hypothesis is based on some previous observation such as noticing that in Novenber many trees undergo color changes in their leaves and the average daily temperatures are dropping. Are these two events connected?

Any laboratory procedure you follow without a hypothesis is really not an experiment. It is just an exercise or demonstration of what is already known.

Formalized hypothesis examples

If skin cancer is related to ultraviolet light, then people with a high exposure to UV light will have a higher frecuency of skin cancer
If leaf color change is related to temperature, then exposin plants to low temperatures will result in changes in leaf color.

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

Formalized hypothesis contain two variables. One is "independent" and the other is "dependent". The independent variable is the one you, the "scientist" control and the dependent is the one that you observe and/or measure the results. For example

If the Frequency of winning is related to frequency of buying lottery tickets.

Independent, dependent.

Practice

Wite 7 Hypothesis, see the examples.

Example

There is a positive correlation between the availability of hours for work and the productivity of employees.

If the size of the molecules is related to the rate of diffusion as they pass through a membrane, then smaller molecules will flow through at a higher rate.

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