We do scientific research because we want to know what is happening in the world around us. The understanding we get from this research helps us make predictions. These predictions can turn into hypotheses. This is closely connected to the problem-solving skill where you gather information in order to make informed decisions.
EXAMPLEFor example, you might want to know when an animal might attack or if somebody will get sick so that you can prevent it in the future.
Anything that can change or be measured or can affect research is called a variable. In scientific research, these variables need to be controlled. We want to focus on specific things so we can understand them better. When we control variables, this allows us to concentrate on just the thing we’re testing.
You may be aware that when an experiment is done, people are placed in different groups, called a control group and an experimental group. A control group is a group of people who receive all of the conditions of an experiment except the variable that's being tested. The experimental group, on the other hand, would be the people who receive all of the conditions of the experiment, including the experimental condition or the variable that's being studied.
Notice the importance of controlling all of the other conditions in the experiment to make sure nothing else is causing the effects that you measure. You make sure the rooms are the same and that both groups are being given water. The only thing that you change is the pill that you want to study.
There are different types of variables that a scientist needs to consider to determine the accuracy of an experiment itself:
EXAMPLEIn an experiment measuring sleep and its effect on intelligence, the independent variable would be the amount of sleep. This is the variable that can be changed, to see what the results would be.
EXAMPLEIn the sleep experiment, sleep is the independent variable, which would mean the dependent variable--the result of the amount of sleep--would be the intelligence of the subjects that is tested.
Dependent variables are measured by something very specific or concrete -- like intelligence measured by test scores -- because research relies on scientific measures.
When doing psychological research, it's important to identify exactly what population is being studied within that research. A population is a category of people who are being studied.
Often, the population being discussed within psychological research is the generalized idea of all human beings and their mental processes. However, sometimes psychological research is more specific so that those populations would be a bit smaller.
EXAMPLEFor example, certain research might target infant girls; this would be one population. Or, it might focus on middle-aged men or businessmen between 20 and 24 years of age, which is a different population.
Realistically, though, you can't test everybody, especially if you're talking about everyone in the entire world, so you take a sample, which is a small selection of people from a population. It is important that the sample is "representative". This means that the sample accurately reflects the characteristics of the population being studied.