The importance of statistics to psychology

Hello my dear readers, you must think that statistics has nothing to do with psychology or has no importance for professionals in the area. However, through this text, we will explain the value of statistics for us psychology students and psychologists.

statistics concept

Statistics is the area that specifically studies the collection, organization, analysis, interpretation and presentation of data. Statistics deals with all types of data, including planning data collection in projects for a survey, experiment, or questionnaire. The word Statistics refers to the discipline of Statistics, which is also a faculty and a field of study within Mathematics. When we say about the statistics of a survey, we are talking about the calculation of data used, for example, mean, median, mode or other.

The importance of statistics in psychology

The importance of statistics is saving time and money for researchers. As an example, we can initially mention its use in the testing area. The psychologist is the only professional who can apply psychological tests. In this sense, one of the ways to validate a psychometric test is to collect a large amount of information from several people and then evaluate all the data, thus resulting in what is most common in a population.

Example: The WISC intelligence test. To assess people’s intelligence, researchers instead of doing millions of interviews, they make a sample, selecting a smaller number than the general population, but representing it as a whole.

There are two reasons for using psychometric tests:

1. The tests were created to measure mental characteristics. (Personality, Psychopathology, Humor, Social Skills, etc.)
2. It is possible to collect large amounts of data and the facility to analyze it. Through a battery of psychometric tests, it is possible to obtain large numbers about the characteristics of the subject. (Ex.: When you are going to get a license, you go to the psychotechnician and through some tests it is possible to verify whether or not you are capable of driving)

In addition to the importance of statistics in the creation, elaboration and application of psychological tests, we can also find statistics in psychology research. And, since statistics is an ally to better understand research results – especially quantitative ones – psychology students and professionals who have already graduated must know at least the basics of this exact science.

An example of using statistics: mean and mode

An example will clarify why it is important to understand the types of measures within statistics, since the raw numbers themselves may not give us a correct assessment. Many people ask about the average salary of a psychology professional. The notion of average is fundamental for us to understand this parameter, which can easily deceive us.

Let’s imagine two groups of psychology professionals. Group A and Group B.

Group A – 10 professionals

2 professionals earn 10,000 reais per month and the other 8 earn 1,000 reais per month.

Group B – 10 professionals

1 trader earns 1,000, 1 trader earns 2,000, 1 trader earns 3,000, 1 trader earns 4,000, 1 trader earns 5,000, 1 trader earns 6,000, 1 trader earns 7,000, 1 trader earns 8,000, 1 trader earns 9,000, 1 trader earns 10,000.

The numbers above are raw numbers. Now let’s talk about the average salary of each group.

Group A has an average salary of 2,800 reais.

Group B has an average salary of 5,500 reais.

In both groups, looking at the raw numbers and the averages, we will see that the average salary does not seem to correspond. The professional who earns 10,000 reais in Group A and sees that the average salary for his group is 2800 will see that he is earning well above the average, while the professional who earns 1,000 will also see that he earns a different amount than the average, in the case , much lower. It is interesting to note that in both cases, the average calculation is correct, but the final number is “misleading”.

Another way of analyzing the raw data would be by calculating the mode, which, according to Spiegel, “is the value that holds the largest number of observations, that is, the most frequent value or values, or even “the value that occurs most frequently”. in a dataset, i.e., the most common value”

In Group A, we would see that the mode, the most frequent number, is 1000 reais. If in a group of 10, only 20% earn 10,000 and 80% earn 1,000, saying that the salary is close to the fashion, 1,000 reais would be closer to the truth than saying that the average salary is 2,800 reais.

In Group B, we cannot indicate a mode, since no value is repeated.

Anyway, when observing the salaries of these 20 professionals, how can we understand how much a psychologist earns? The methods of answering this question therefore come from statistical analysis.

Another way of displaying the results would be to create a graph, showing the proportion of each salary in the whole – which can also be done using statistics.

We would then say that

In Group A – 80% earn 1,000 reais and 20% earn 10,000

In Group B, in which individual data are more disparate, we could create 3 categories:

1) Below 3500 reais – 30% percent

2) Between 3500 reais and 7000 reais – 40% percent

3) Above 7000 reais – 30% percent.

I would like to make it clear that these salary figures are fictitious.

Conclusion

Statistics is important in psychology for the validation, application and evaluation of psychological test results. In addition, it is a tool that psychology students and professionals need to know in order to know how to deal with raw data in research. In the text, we gave some examples of how the numbers, resulting in a given population (Group A and B), can be interpreted from two simple statistical tools, the mean and the mode.

These two tools are simple and many other tools, more complex and complicated, are used to display the results in graphs, to calculate biases, to test the validity of the results, among other needs of researchers.

Because it is an exact science and requires skill in mathematics and more elaborate calculations, statistics, during the psychology course, is generally a strange discipline for most students, who are more connected to the human and natural sciences than to the exact Sciences. However, as shown in the text, knowledge of statistics is extremely important for understanding quantitative research and is also often necessary in qualitative research.

References:

SPIEGEL, Murray R. Statistics. São Paulo: McGraw-Hill do Brasil, 1976.

Winograd, Monah, Milena Vasconcelos Martins de Jesus, and Emmy Uehara. “Qualitative aspects in the practice of neuropsychological assessment.” Science and Cognition/Science and Cognition 17.2 (2012).

Related