Students sometimes confuse the idea of falsifiability with the idea that it means that something is false, which is not the case. What falsifiability means is that if something was false, then it is possible to demonstrate that it is false. One of the hallmarks of pseudoscience is that it makes claims that cannot be refuted or proven false. A variable is a factor or element that can be changed and manipulated in ways that are observable and measurable.
However, the researcher must also define how the variable will be manipulated and measured in the study. For example, a researcher might operationally define the variable " test anxiety " as the results of a self-report measure of anxiety experienced during an exam. A "study habits" variable might be defined by the amount of studying that actually occurs as measured by time. These precise descriptions are important because many things can be measured in a number of different ways.
One of the basic principles of any type of scientific research is that the results must be replicable. Some variables are more difficult than others to define. How would you operationally define a variable such as aggression? For obvious ethical reasons, researchers cannot create a situation in which a person behaves aggressively toward others. In order to measure this variable, the researcher must devise a measurement that assesses aggressive behavior without harming other people.
In this situation, the researcher might utilize a simulated task to measure aggressiveness. Once a researcher has formed a testable hypothesis, the next step is to select a research design and start collecting data.
The research method depends largely on exactly what they are studying. There are two basic types of research methods: descriptive research and experimental research. Descriptive research such as case studies , naturalistic observations , and surveys are often used when it would be impossible or difficult to conduct an experiment.
These methods are best used to describe different aspects of a behavior or psychological phenomenon. Once a researcher has collected data using descriptive methods, a correlational study can then be used to look at how the variables are related. This type of research method might be used to investigate a hypothesis that is difficult to test experimentally. Experimental methods are used to demonstrate causal relationships between variables. In an experiment, the researcher systematically manipulates a variable of interest known as the independent variable and measures the effect on another variable known as the dependent variable.
Unlike correlational studies, which can only be used to determine if there is a relationship between two variables, experimental methods can be used to determine the actual nature of the relationship—whether changes in one variable actually cause another to change. The hypothesis is a critical part of any scientific exploration. It represents what researchers expect to find in a study or experiment.
In situations where the hypothesis is unsupported by the research, the research still has value. Such research helps us better understand how different aspects of the natural world relate to one another. It also helps us develop new hypotheses that can then be tested in the future.
Ever wonder what your personality type means? Sign up to find out more in our Healthy Mind newsletter. Castillo M. The scientific method: a need for something better? Your Privacy Rights. In an experiment, the dependent variables are those that the scientist measures before, during, and particularly at the end of the experiment to see if they have changed as expected.
The dependent variable must be stated so that it is clear how it will be observed or measured. In any real-world example, many, many variables MIGHT affect the outcome of an experiment, yet only one or a few independent variables can be tested.
Other variables must be kept as similar as possible between the study groups and are called control variables. To avoid this problem, a good study will be set up so that each group contains students with a similar age profile.
In a well-designed educational research study, student age will be a controlled variable, along with other possibly important factors like gender, past educational achievement, and pre-existing knowledge of the subject area. Improve this page Learn More. Skip to main content. Module 1: Introduction to Biology. Search for:. Experiments and Hypotheses Learning Outcomes Form a hypothesis and use it to design a scientific experiment.
Practice Questions Determine whether each following statement is a scientific hypothesis. Air pollution from automobile exhaust can trigger symptoms in people with asthma. This statement is not testable. This statement is not falsifiable. This statement is testable and falsifiable. Show Answer d: Yes. This could be tested with a number of different kinds of observations and experiments, and it is possible to gather evidence that indicates that air pollution is not linked with asthma. Show Answer a: No.
HPV causes cervical cancer. People should not have unprotected sex with many partners. People who get the vaccine will not get HPV. The HPV vaccine will protect people against cancer. Show Answer Hypothesis A is not the best choice because this information is already known from previous studies. This statement will make an excellent hypothesis for the next study.
The researchers should first test hypothesis C—whether or not the new vaccine can prevent HPV. Practice Questions The scientists who are researching the effectiveness of the HPV vaccine will test their hypothesis by separating 2, young women into two groups: the control group and the experimental group. Which of the following groups most likely represents the control group? This group is given a placebo. This group is deliberately infected with HPV.
This group is given nothing. This group is given the HPV vaccine. Which of the following groups most likely represents the experimental group? Show Answers a: This group is given a placebo. A placebo will be a shot, just like the HPV vaccine, but it will have no active ingredient. The experimental group will receive the HPV vaccine and researchers will then be able to see if it works, when compared to the control group. November 4, at am. This is an idea that may explain phenomena in the natural world.
Making a hypothesis is one part of the process scientists use to make new discoveries. Before making a hypothesis, scientists may read about a topic to understand it better. They may talk with other scientists about it. Until confirmed, or disproven, such answers may be described as hypothetical ones. For example, a team of biologists was studying how whales communicate. They knew that mother and baby humpback whales call quietly to each other when they migrate.
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