A Statistics Item

Errors of the first and second kind

Two types of errors

Prof.Dr.Faik Fadhil Ahmed Al-Samarai,Bilad Al Rafidain University College-Department of Accounting.

  Several students of research projects ask me about "the nature of hypothesis testing", or sometimes I get excited by reading a lot of posts on Social media about that. Therefore, I decided to address the topic to simplify it so I can provide some of its requirements for beginners in scientific research or for those who are not specialized but those who are decision makers and through an example meaning Presented inductively (Induction) according to the following order:

For example: "If a researcher in the pathological analysis laboratory is looking into the validity of a specific plasma to be a valid vaccine against the Coronavirus or not", his/her analytical study will be according to the following steps of scientific research:

1- Determining the research question: Is there a positive effect as a result of using the proposed serum against Coronavirus?

2- The two research hypotheses: From the requirements of the work, the following two hypotheses are formulated, which serve as a temporary solution to the research question:

A- The null hypothesis (the text): There is no effect of the proposed vaccine against the Coronavirus.

B - The alternative hypothesis (its text): There is a positive effect as a result of using the proposed vaccine against the Coronavirus.

3- Testing and discussing the results:

Depending on the data available to the researcher as a result of his research procedures, his decision is in one of the following two possibilities:

The first possibility: when the results indicate the necessity of (rejecting the null hypothesis and accepting the alternative hypothesis).

Discussion: The decision means that the plasma has a positive effect when it used.

But the truth of the matter is that there is no positive effect as a result of using it without the knowledge of the researcher.

Here, the researcher has made a mistake with the first type, which is called alpha.

The second possibility: when the results indicate the necessity of (accepting the null hypothesis and rejecting the alternative hypothesis).

Discussion: The decision means that there is no positive effect as a result of using the proposed vaccine against the Coronavirus, when in fact there is a positive effect without the knowledge of the researcher.

Here, the researcher has fallen into a mistake of the second type, called beta.

Here comes to mind:

How many students succeeded as a result of cheating in the exam, how many students failed as a result of bad exam questions, how many accused became innocent and vice versa as a result of misleading the judiciary, and how much state budget was wasted as a result of decision-makers reliance on incorrect information or lack of experience and knowledge of decision-makers, and how many doctors made a mistake in their decisions as a result of providing them With insufficient laboratory information. How many people occupied a position that does not suit him, and how many?

Our recommendation: is to provide the correct requirements for institutional work and decision-makers, starting with their correct choice and continuing to provide accurate data according to the steps of the scientific method. (Pictures are from the statistics book by Dr. Mahmoud Al-Mashhadani)

May Allah save Iraq and its people.

Prof.Dr.Faik Fadhil Ahmed Al-Samarai,Bilad Al Rafidain University College-Department of Accounting.