Lecture 2A: The Scientific Method

Question 1

Define the scientific method

Answer 1

A method of research used by biologists that consists of specific steps that includes experiments and careful observation

Question 2

What are the 6 steps of the scientific method?

Answer 2

1. make observations
2. ask a research question
3. develop a hypothesis
4. make predictions of what will happen
5. design and conduct an experiment to test the hypothesis
6. if the experiment does not support the hypothesis, revise the hypothesis and try again; if the experiment does support it, form another hypothesis

Question 3

Define scientific hypothesis

Answer 3

an educated, potential explanation for an observation

Question 4

What does it mean for a hypothesis to be testable and falsifiable?

Answer 4

The hypothesis must be able to be tested through an experiment or further observation to determine if it is false

Question 5

What is an independent variable?

Answer 5

The variable within an experiment that the researcher intentionally manipulates

Question 6

What is a dependent variable?

Answer 6

The variable within an experiment that the researcher predicts will be affected and measured to determine the effect

Question 7

What is a null hypothesis? What is its purpose?

Answer 7

A statement that the independent variable will have no affect on the dependent variable. The purpose of the null hypothesis is to limit bias by assuming it is correct until the experiment supports otherwise and the null hypothesis can be rejected.

Question 8

What is an alternative hypothesis?

Answer 8

The opposite of the null.

A statement that the independent variable will have an affect on the dependent variable

Question 9

What is the experiment/treatment group?

Answer 9

The group that receives treatment within the experiment

Question 10

What is the control group?

Answer 10

The group that receives no treatment or a placebo treatment within an experiment

Question 11

How would a researcher set up the control group and the treatment group, in terms of independent variables?

Answer 11

Set up the groups so that the only difference between the control group and the treatment group is the INDEPENDENT VARIABLE

Question 12

What are the 8 components of experimental design?

Answer 12

1. independent variable
2. dependent variable
3. groups in the experiment (control and treatment)
4. standardized variables
5. replication
6. data collection
7. statistical analysis
8. conclusion

Question 13

When choosing subjects to be in the experimental vs. control groups, what is the best way for a researcher to pick? why?

Answer 13

RANDOM. To limit bias

Question 14

What are standardized variables?

Answer 14

Variables within an experiment that are exactly the same between all groups. It is crucial to identify these before conducting the experiment so that you can determine the results are just from the independent variable
ex. when testing a fertilizer for plant growth, identifying that water could be an extraneous variable and then adding the same amount of water to all groups to ensure it does not affect the results

Question 15

What is replication? why is it important in experiments? What are some restrictions to increasing replicate size?

Answer 15

The number of individuals in the control and experimental groups.
Important to have as many replicates as possible for the means of the experiment because it ensures your results are not just chance.
Large sample sizes can be more costly, time consuming, and use more resources

Question 16

What is data collection in an experiment?

Answer 16

The data a researcher will collect from the treatment and control groups. How it will be measured, when it will be measured, how often, etc. must be VERY specific.

Question 17

What is data collection in an experiment?

Answer 17

The data a researcher will collect from the treatment and control groups. How it will be measured, when it will be measured, how often, etc. must be VERY specific.

Question 18

How is statistical analysis used as a component of an experiment?

Answer 18

It is used to determine the probability of the results of an experiment being due to chance ie. it provides a measure of how confident a researcher can be in the results;
Science requires that to be able to reject the null hypothesis, there must be a statistically significant difference between the results of the control group vs. the treatment group

Question 19

What is the conclusion in an experiment?

Answer 19

The last step of an experiment is to determine a conclusion for the results. A very specific statement that summarizes the findings.

Question 20

What is a controlled experiment?

Answer 20

One that is meant to compare a treatment group to a control group, where ideally, the only difference is the independent variable (or the variable the experiment is testing.) All other extraneous variables have been identified and either standardized to the best of the researcher’s ability or ruled out by the use of a control group.