Lab #2: Scientific Inquiry: Formulating a Hypothesis

Three criteria necessary for choosing a question that can lead to a good hypothesis:

1. Can the question be answered? If there is no means to test the hypothesis, it is of no value 2. Can the question be answered "no"? We must have a hypothesis that can be refuted (proven false); if there is no possibility of proving that a hypothesis is false, then it cannot be tested. 3. Does the question specifically address the observation? A hypothesis should focus on a limited, specific, well-defined problem.

Process of scientific inquiry:

1. Observations 2. Hypothesis 3. Experiments 4. Results 5. Interpretation of results 6. Conclusion 7. Revised hypothesis

Scientific Inquiry stages:

1. Observations lead to formulation of a research question 2. The question leads to an educated guess (hypothesis) about the answer. Prior knowledge or research and even intuition can contribute to the formulation of a hypothesis. 3. The value of the hypothesis in explaining a phenomenon or answering a question must be tested in a way that allows the hypothesis to be proven false. 4. The results must be interpreted 5. A conclusion about the value of the hypothesis is based on the interpretation of results

Were both of the data sets significantly different or not significantly different?

There were significantly different.

Improvements for lab #2

Using multiple samples

independent variable

What is being changed. Ex: light intensity, temperature, density, etc

Dependent variable

What is being measured. Ex: aggressive behavior

What was the hypothesis in lab #2

Young and old leaves of a species do not have significantly different stomatal densities.

What was concluded about stomatal density of young vs. old leaves

Younger leaves have a greater amount of stomatal than the old leaves

T-test

a statistical test that will be used to compare the stomatal densities

Scientists ______ ideas, theories, and hypotheses only because they cannot show them to be false.

accept

A hypothesis is ________ only if our data does not contradict it.

approved

When exhaustive experiments and observations consistently support an important _______, it is accepted as ______.

hypothesis... theory

You will make epidermal peels from the _____ __________ of each leaf.

lower epidermis

Sources of error for lab #2 include...

miscounting and/or recounting

Hypothesis can never be considered to be _____ as the result of experiments or observations.

proven

stomata

small pores in the epidermis that allow gas exchange in the interior of a leaf.

Replication

taking multiple samples

What does a p-value greater than 0.05 indicate?

that the two data sets are not significantly different

What does a p-value less than 0.05 indicate...

that the two data sets are statistically different

Scientific theories are...

the solid bedrock of science

Null hypothesis

It states the alternative possibility that no effect occurs due to an experiment treatment. Usually phrased negatively and is often easier to test because it's easier to determine if the data contradicts the hypothesis

What plant did we use in this experiment?

Schefflera Gold Capella