home
about the project
Medical news
For authors
Licensed books on medicine
<< Previous Next >>

NON-PARAMETRIC METHODS FOR ASSESSING THE RELIABILITY OF RESULTS OF A STATISTICAL STUDY. COMPLIANCE CRITERION (CHI-SQUARE)

LESSON PURPOSE: To master the methodology for calculating and using the correspondence criterion to determine the significance of the discrepancy between several compared groups of studied phenomena

LESSON METHODOLOGY: Students independently prepare for a practical lesson in the recommended literature and complete their individual homework. The teacher within 10 minutes checks the correctness of homework and indicates the mistakes made, checks the degree of preparation using testing and an oral survey. Then, students independently calculate the compliance criterion to determine the accuracy of the discrepancy between several compared groups of studied phenomena, evaluate the data obtained and formulate a conclusion. At the end of the lesson, the teacher checks the students' independent work.

TEST QUESTIONS:

1. When is the chi-square metric applied?

2. What is the calculation of the indicator? 2 based on?

3. What is the "null hypothesis"?

4. What are the steps involved in calculating the chi-square compliance criterion?

5. How is the number of degrees of freedom determined when calculating the compliance criterion?

6. How is the result of the compliance indicator evaluated?

7. When are differences between several compared groups evaluated as significant?

SUMMARY OF TOPIC:

The reliability of differences and the relationship of phenomena with factors can be determined when calculating the compliance criterion. Correspondence criterion? 2 is used for statistical evaluation of the law of distribution of empirical variational series and for proving the significance of differences between two or more sample populations. The compliance criterion is applied when the research results are presented in absolute values ​​and the outcome has many gradations (recovered, discharged with improvement, worsening, died), and also if the subject has several signs (several age groups, several treatment methods). The criterion is based on the assumption (null hypothesis) that there is no difference between the values ​​obtained as a result of sample observation and theoretically calculated. The more actual values ​​differ from the expected ones, the greater is the certainty that the factor under study has a significant effect.

The compliance criterion is calculated by the formula

An example of calculating a compliance criterion. Stage 1 - we formulate the null hypothesis - the introduction of an influenza vaccine did not affect the incidence of influenza. In this case, the distribution of sick and not sick in the two observation groups should be the same and correspond to the final distribution.

Does influenza vaccine affect influenza incidence

It also calculates the expected values ​​for those who are ill and not ill with the flu from among those not vaccinated.


TASK FOR INDEPENDENT WORK

Task number 1. Calculate the compliance criterion? 2 and determine whether the difference between the numbers obtained in the process of statistical research and the “expected values” is significant or not significant.

Task 1

Determine if marital status affects student performance

Task 2

To establish whether participation in hostilities affects the incidence of post-traumatic stress disorders in military personnel

Task 3.

Determine whether ad media affects a patient’s decision to consult a dentist

Task 4.

To establish whether the presence of Helicobacter pylori infection affects the frequency of pre-tumor pathology and gastric malignancies

Task 5.

Determine whether the season affects the nature of weight changes in children

Task 6.

To determine whether the profession affects the prevalence of clinical forms of borderline mental disorders (PPR)

Task 7.

Determine whether age affects the use of sedatives and sleeping pills

Task 8.

To establish whether the nosological form of the disease affects the effectiveness of the use of demineralized bone implants in pediatric traumatology and orthopedics

Task 9.

To establish whether work experience affects the incidence of hypertension in teachers

Task 10.

To establish whether the health status of students studying in various faculties of medical universities is different

Task 11.

To establish whether the marital status affects the level of physical development of primary school children

Task 12.

To establish whether the thoroughness of the patient's recommendations of the doctor affects the nature of the course of gastric ulcer

Task 13.

To establish whether the acidity of gastric juice affects the blood condition in patients with gastric cancer

Task 14.

To establish whether fatness affects the mental development of the child

Recommended literature for students:

• Lisitsyn Yu.P. Social hygiene (medicine) and healthcare organization. Kazan, 1999, p. 307 - 308

• Serenko A.F., Ermakov V.V. Social Hygiene and Health Organization, M, 1984, p. 139 - 149.

• Yuryev V.K., Kutsenko G.I. Public health and healthcare. S-P, 2000, p. 197 - 199.

• Public health and healthcare. Ed. V.A. Minyaeva, N.I. Vishnyakova M. “MEDpress-inform.”, 2002. - p. 108-109, 113-114.

• Zaitsev V.M., Livland V.G., Marinkin V.I. Applied Medical Statistics. S.-P. The Tome, 2003.
<< Previous Next >>
= Skip to textbook content =

NON-PARAMETRIC METHODS FOR ASSESSING THE RELIABILITY OF RESULTS OF A STATISTICAL STUDY. COMPLIANCE CRITERION (CHI-SQUARE)

  1. ASSESSMENT OF RELIABILITY OF RESEARCH RESULTS
    PURPOSE OF THE LESSON. Master the parametric methods for assessing the reliability of the results of a statistical study and master the methodology for calculating the errors of average and relative values, the confidence limits of these values, the method of calculating the reliability of the difference between the average and relative values. LESSON TECHNIQUE. Students independently prepare for a practical lesson on the recommended
  2. Reliability of the research results and personal contribution of the author
    The reliability of the scientific provisions and conclusions formulated in the thesis is ensured by the use of a set of mutually complementary diagnostic methods that are adequate to the purpose and objectives of the study, the use of extensive factual material and its comprehensive analysis, representative sample of the examined, careful quantitative and qualitative analysis, as well as correct application
  3. Evaluation of the results of activities and human behavior, the team - a powerful method of military psychological research
    Assessing the role of the method in the success of studying any problem, the outstanding Russian researcher-experimenter I.P. Pavlov wrote: “The method is the very first basic thing. The severity of the study depends on the method, on the mode of action. With a good method and a not very talented person can do a lot. And with a bad method, a brilliant person will work in vain, will not receive valuable, accurate
  4. Evaluation of the results of sanitary-helminthological studies
    A correct assessment of the results of sanitary-helminthological studies of environmental objects is of great importance both for scientific work and for practical sanitary service. In order to be able to compare the results of their own research in dynamics, as well as those of other authors, it is necessary to adhere to certain standard indicators. Each sample should be
  5. AVERAGE VALUES, THE METHOD OF THEIR CALCULATION AND ASSESSMENT OF RELIABILITY
    LESSON PURPOSE: To master the basics of variation statistics, the skills of calculating and evaluating the reliability of average values. LESSONS: The students prepare for the practical lesson on the recommended literature and complete their individual homework. The teacher within 10 minutes checks the correctness of homework and indicates the mistakes made,
  6. Assessment of the reliability of the relationship of self-esteem and professional orientation of students - psychologists
    The task of correlation analysis is to establish the direction (positive or negative) and form (linear, nonlinear) of the relationship between the varying features, measure its tightness, and, finally, to check the significance level of the obtained correlation coefficients. The criterion for selecting “sufficiently strong” correlations may be as the absolute value of the correlation coefficient itself (from 0.7
  7. Mathematical and statistical analysis of the results
    Based on the data obtained, it is possible to construct schemes of significant relationships between the obtained indicators. 1st group {foto14} Fig. 27 The structure of the hierarchy between significant indicators (greater than 0.75) that affect the aggressiveness of group 1 {foto15} Fig. 28 Based on the data obtained, it is possible to construct schemes of significant connections between the obtained indicators. 2 group
  8. ASSESSMENT OF STATISTICAL INDICATORS
    The most important indicators are heart rate,?, Max (s), Min (s),? X, V (%). Typically, the heart rate ranges from 60 to 90 in 1 minute. With high-quality filtering of the record, the difference between Max (s) and Min (s) - the indicator? X corresponds to the amplitude of the natural fluctuations of the rhythmogram and usually decreases with a deterioration in the functional state of the CCC. In the presence of at least one arrhythmic episode (for example,
  9. STATISTICAL STUDY METHOD
    LESSON PURPOSE: To familiarize students with the sequence of statistical research, to teach self-planning and statistical research program, the correct determination of the unit of observation and accounting signs, to familiarize with the methodology of collecting material for its processing and analysis. LESSON METHOD At the beginning of the lesson, the teacher gives a definition
  10. METHODS BASED ON THE STATISTICAL TRANSFORMATIONS
    STATISTICAL ANALYSIS Statistical methods are used to quantify HRV in the studied period of time. When using them, a cardiointervalogram is considered as a set of consecutive time intervals (numerical values ​​of the duration of R – R intervals). The main indicators of statistical analysis: Khsr. (Mathematical expectation, M, Меаn, RRNN) -
  11. STATISTICAL PARAMETERS OF PSYCHODIAGNOSTIC RESEARCH
    Each psychological sign, as a result of measurement, can be characterized by several parameters. ACCURACY (reliability) of measurement - quality reflecting the proximity of their result to the true value of the measured quantity. High accuracy corresponds to small systematic and random errors. CORRECTNESS OF MEASUREMENT - quality, reflecting the proximity to zero of systematic
  12. Assessment of the clinical and prognostic value of ventricular arrhythmias, methods for the study of arrhythmogenic substrate
    Assessment of the clinical and prognostic value of ventricular arrhythmias, methods for the study of arrhythmogenic
  13. Criteria for assessing knowledge and skills
    Assessment of knowledge, abilities and skills of students is the final stage of most types of control. At the same time, objectivity and accuracy should be ensured based on the evaluation criteria. For each discipline individually, the department should develop uniform criteria that should reflect the degree of conformity of the level (goals) of training for a given course (section, topic) to the level of its mastery
  14. 7. Criteria for assessing the quality of students' knowledge:
    on the test Testing: 1) with 71% of positive answers - the test. 2) with less than 70% of positive answers, an oral interview throughout the section. If the answer is yes, the offset. On the exam: • first stage: with 71% of the positive answers of the test - a positive assessment; • second stage: with the correct answer to two practical tasks (viewing the micropreparation and
Medical portal "MedguideBook" © 2014-2019
info@medicine-guidebook.com