Computerized Lecture Notes on Science PDF

Knowledge Information: The subjects of knowing and learning the process. Ways to Learn/ Obtain Alternative Knowledge to Science 1- Authority (e.g. mothers, fathers) 2- Customs 3- Common sense 4- Media 5- Personal experiences PS: They are not objective, bu...

Knowledge Information: The subjects of knowing and learning the process. Ways to Learn/ Obtain Alternative Knowledge to Science 1- Authority (e.g. mothers, fathers) 2- Customs 3- Common sense 4- Media 5- Personal experiences PS: They are not objective, but science is. SCIENCE In a dictionary, science is defined as follow: Organized knowledge that chooses a part of the universe of events as its subject and tries to derive laws based on experimental methods and reality. For any scientific research it must be “systematic”. In short, science is a body of systematic knowledge whose validity is accepted. Science is a product and the method followed to obtain is the scientific method. THE BASIC FUNCTIONS OF SCIENCE 1- Comprehension: “What is?” It’s about answering the question and portraying the existing situation as it is. 2- Explanation: “Why?” For the purpose of finding the relationship between the causes of observed things and developing theory. “theory” 3- Control: It aims to actually transfer the information through comprehension and explanation functions to applications and to control natural and social events. PS: Theory is the most advanced explanation. THE CLASSIFICATION OF SCIENCES 1- Basic Sciences vs. Applied Sciences Mathematics Engineering 2- Positive Sciences vs. Social Sciences Biology History THE VALUE OF SCIENCE 1- Practical Value of Science Science provides great benefits to us, through technology in both our individual and social lives, “modernization.” 2- Intellectual Value of Science Science satisfies people’s desire to know and their curiosity. It provides people with the opportunity to understand the universe. 3- Moral Value of Science Science gives people a scientific method. It teaches people to handle to problems in a patient, detailed and foresighted manner. BASIC FEATURES OF SCIENCE 1- Science is factual. However, it is both unnecessary and impossible for science to deal with all phenomenons occurring in the universe. 2- Science is logical. Science uses logical thinking and rules of inference when verifying a hypothesis or theory. 3- Science is objective. A scientific result cannot be monopoly of individuals or groups. Theories are valid until they are replaced by new ones. 4- Science is critical. In science, no truth is ever immortal. This feature of science is the main reason for it’s development. 5- Science is generalizing. The aim should be to derive a rule from the specific to the general. 6- Science is constantly changing. It is not static. 7- Science is selective. The phenomena under scientific investigation is limited among natural or social events. 8- There are predictions in science. FACTS Facts are concrete by nature, for example, the fact that we are currently taking the Research Methodology class in the Conference Hall. CONCEPTS Concepts do not actually exist around us like facts we have created them in our minds. They are symbolic expressions that collect and summarize similar features of the same type of phenomena and are produced as a result of abstraction. Example: House (A concept) Ali’s Villa Ayşe’s Slum Ahmet’s Apartment (Facts) Gender: lower abstraction Personality: lower abstraction SCIENTIFIC LAW Scientific law are casual relationships that are valid in every context and have reached a certain level of reliability. THEORY It is a series of information derived from scientific knowledge that is open to verification but has not yet been [fully] verified. It is the theory that connects observation and experimental results. Theories are abandoned after being refuted. HISTORY OF SCIENCE The development of science divided into four stages: 1- The phase of collecting empirical information based on observation by Egyptian and Mesopotamian civilizations. 2- The phase in which the ancient Greeks (Ionians) established rational systems to explain the universe. 3- The effort to reconcile the Greek philosophy of the Middle Ages with the religion of Christianity and the phase of successes in the Islamic World. 4- The modern scientific phase with post-Renaissance developments. The history of science begins with the history of urbanization.  - The first civilizations began in major valleys such as Euphrates. - The Sumerian civilization developed in Mesopotamia around 3000 BC along with agriculture, they processed copper and obtained bronze. They wrote their product calculations in cuneiform on clay tablets. Before 2500 BC, they were using multiplication tables. The Sumerians were making area and volume calculations and taking volume 3 as the II. HISTORY OF SCIENCE STAGE 1 The Babylonians, who succeeded The Sumerians, established temple schools. They made progress in mathematics and astronomy e.g., tables for taking square roots and solving second/third degree equations. They succeed in dividing a circle into 360’ and an hour to 60 minutes. By making astronomical observations Babylonians calculated the length of the year with an error of 4.5 minutes and found that lunar eclipses occurred every 18 years. STAGE 2 (The phase in which the ancient Greeks) Ancient Greek science was born in Ionia on the western coast of Anatolia. 1- Thales (624- 547 BC) is considered the first philosopher. His first scientific view put forward the hypothesis that the universe was composed of water. This thought represents the transition from mythological thought to rational thinking. 2- Pythagoras (570- 490 BC) established an academy in the city of Crotone. (Southern part of the Italy) According to Pythagoras numbers are the building block of the universe. It is considered the beginning of rationalist thought. 3- Democritus (500- 404 BC) is considered the founder of the atomic universe. 4- Socrates (470- 399 BC) with Socrates the system of thought turned from the universe to humans and moral philosophy. Whose aim was humans and their behaviors, emerged. 5- Plato (407- 347 BC) founded a school called Academy in Athens. It was written on the door of the school. “Those who do not know geometry cannot enter here.” He believed that the spherical earth was at the center of the universe and that the sun, moon, and planets revolved around the earth at different speeds. PS: Plato’s influence on science has been not inspiring but stalling in the path of progress!  6- Aristotle (384- 322 BC) founded the Lyceum in Athens. Aristotle believed that for humans to understand the natural world, they should collect all tangible facts they could. He accumulated great knowledge in biology, astronomy, and physics. With the conquest of Alexander the Great Greek culture moved to new centers. A transition was made from intellectual science, which was metaphysical, to empirical science, which was based on observational investigation. This period is called as the Hellenic Age Ancient Greek thinking was deductive. 7- Archimedes (287- 212 BC) who brought together induction and deductions is considered the first scientist. ***** STAGE 3 The effort to reconcile the Greek philosophy with Christianity. Science in Medieval Europe The thousand-year period between the end of ancient civilizations and the beginning of the Italian Renaissance (4th and 14th century AD) was a dark period for Europe. Aristotle was the sole authority. The idea that only faith, not reasoning, can save people has gained dominance. The pressure of religion and magic on thinking was enormously big! Religion has established its authority in science as well as in many aspects of daily life. During this period, a number of encyclopedic studies were made on Greek thoughts science in the Islamic World. During the 400-year period between 8th and 12th centuries scientific thought developed in the Islamic World. During the period, Greek works translated into Arabic. In this period, they advanced in algebra and geometry. Arabs brought the Indian decimal system. Although studies in chemistry have not gained a complete independence from alchemy, they have started on the right scientific path. The West in The Scholastic Period - German emperor Charlemagne started an education movement in 787 (universities) - Faculty members guilds are established in Bologna and Paris, the name of university comes from here. - The 13th century is the century in which the birth of science was born. Men have begun to seek the truth by examining rather than following the world of ancient writers of bible. - Scientific works written in Latin* Renaissance and Science - The renaissance was beneficial to development of science by breaking the dominance of religions bigots. This period, which is lively and creative in art and literature, is a period of stagnation* for science. - Leonardo Da Vinci was a great painter, sculptor, architect, scholar, engineer, and philosopher. Leonardo said that real science begins with observation* and if mathematical reasoning is applied to the information obtained from this observation, the information will be stronger*. He suggested the earth is a planet like other planets. - Copernicus (1473-1543) proposed “heliocentric” (sun-centered) system, instead of Ptolemy’s “geocentric” (earth-centered) system. - The church banned it until 1882. - Kepler (1571-1630) took the second big step in astronomy. 1) First law: Each planet moves in an ellipse with the sun at one of its centers. 2) Second law: the line connecting a planet to the sun weeps equal areas in equal time intervals. 3) Third law: the square of the orbital period of a planet is directly proportional to the cube of the main axis length of the ellipse it orbits. - Galileo Galilei (1564-1642) combined experimental and mechanical mastery with mathematical formulas when explaining how objects move, it is acceleration*, not speed, shows external effects. - Isaac Newton (1642-1727)’s greatest work was “mathematical principles of natural philosophy” which is still considered the greatest science book. He discovered the law of universal gravitation. Any two objects in the universe attract each other in direct proportion to the product of their masses and inversely proportional to the square of the distance between them. - The 18th century is the “age of enlightenment” in France French intellectuals believed that reason and science are sufficient for a new worldview that would not require the religion. - Belief in science and progress is the most distinctive feature of the 18th century.  - The 19th century was the convergence of science and technology. One of the most important developments was the establishment of product-oriented research laboratories. The products developed in the laboratories were mass-produced in the factories. - Philosophy and philosophy of science separated by clear boundaries. - People believed science would find a solution to every problem. - 20th century is the period of the “technology explosion.” THE SCIENTIFIC METHODOLOGY Characteristics of Science - Impartiality - Accurate measurement - Proving - What it is, not what should be. (like positive economics and normative (not scientific, it is judgmental) economics) - Science can be both static and dynamic. Deductions vs. Induction observation theory 0hypothesis pattern observation tentative hypothesis confirmation theory Deduction: Reasoning and drawing conclusions for special causes based on general propositions. (Aristotle) Induction: Generalizations obtained by systematically examining observations and experiments. (Bacon) The Scientific Method - It is considered the most reliable way of solving problems. - It is a synthesis of Bacon’s inductive and Aristotle’s deductive approaches. Its steps: 1- Sensing the difficulty (the problem) 2- Defining the problem 3- Predicting the solution 4- Determining of observable testers (verifiers and falsifiers) 5- Conducting trials and evaluations 6- Reporting Basic Assumptions of the Scientific Method 1- There are systematic cause-effect relationships between events. 2- Events can be examined. 3- Valid and reliable information can be collected through the synthesis of inductive and deductive approaches. 4- Events can be explained without relying on metaphysical views. PS: Science tries to test metaphysical views, doesn’t completely deny it. Scientific Research Research is the process of finding a solution to a problem as a result of examining and analyzing various factors. Economic Research It is a set of principles and techniques required for the systematic collection, processing, analysis, and interpretation of data in order to assist “economic agents” in their decision process. Key Features of Economic Research 1- Objectivity: The test results should be evaluated objectively. 2- Validity and Reliability****: (Validity) to extent does to research explore the concept it is intended to investigate? (Reliability) to what extent can the research results be generalized? PS: Validity is sometimes problematic in Economic research. 3- Systematic Process: Everything, including data collection, should be done systematically. 4- Currentness: The data must be up to date. 5- Appropriate: Timing should be taken into consideration so that the research process is not affected by external conditions. 6- Eligibility: The method of data collection must be appropriate. Research Examples: Employee behaviors Performance Absenteeism Portfolio Models Consumer Behaviors Types of Research 1- Applied Economic Research It is the research conducted to solve specific problems that arise within/by economic agents and the results obtained. Example: A company that wants to combine paperless office and personal computers in a network is researching how many house its employees spend on the computer in a given week. 2- Basic Economic Research Research conducted to increase understanding problems commonly seen within/by economic agents and to seek solution methods.  These are researches: - Carried out to expand boundaries of knowledge. - They don’t contain the solution to a specific problem. - The application of such research results takes time. PS: Scientific methods need to be applied in basic and applied research. Scientific Research Scientific research is finding the problem, collecting, and analyzing data, and drawing valid conclusions from them. It is a logical, orderly, and meticulous step by step method that focuses on problem solving objectives. Note: Scientific methods need to be applied in basic and applied research PS: Scientific research is systematic! Characteristics of Scientific Research***exam question 1- Purpose 2- Care/Attention (Riga) 3- Testability 4- Replicability 5- Accuracy and reliability (precision and confidence) 6- Objectivity 7- Generalizability 8- Understandability Ex: A manager wants to examine how employee’s commitment to her organization can be increased. It is applied research. It focuses on a specific problem. 1- Purpose: The research should have a specific purpose and objective. In the example, the aim is to increase employees’ loyalty to the business. Increasing commitment to business benefits business in various ways e.g., less turnover. 2- Care/Attention: A good theoretical foundation and methodological design shows that you care about research. Let’s assume the manager invited 10 employees and asked them what should increase their loyalty to the company. Only with those answers, the managers make various decisions. ***Her entire approach to research is not scientific, because the opinions of these people may not reflect the opinions of all  employees, for example, some factors affecting loyalty may not have been mentioned by these 10 people. 3- Testability: After interviewing randomly selected employees and reviewing previous research in the field of organizational commitment, the researcher develops hypotheses on how to increase employee commitment. These hypotheses are tested by applying various econometric methods. 4- Replicability****: The results obtained hypothesis testing should support the results obtained from other studies conducted in the same way. In such a case, our confidence will increase. If the results obtained from other studies on the same subject are not consistent, there may be an error in the research process. 5- Accuracy and Reliability (Precision and Confidence): In social sciences, it is very difficult to obtain definitive conclusions based on data analysis. Measurement errors and other problems can cause our findings to be biased and inaccurate. The research is designed so that results are close to reality. Reliability shows how close the results we obtain based on the sample are to reality. It indicates the probability of accuracy of the results obtained. (confidence level) 6- Objectivity: The results obtained by interpreting the results of data analysis should be objective. It should be based on facts derived from data. IT shouldn’t be based on the subjective and emotional values of the research. 7- Generalizability: It shows the applicability of the results obtained from the research from one economic agent to other. The fact that the results obtained have a wider application area shows that the research is more useful. 8- Understandability: The explanation of the problem and the solution obtained should have a simple structure. A complex research design shouldn’t be used. Ex: Let’s assume that there is a relationship between 3 variables and firm commitment. If a change in these variables increases loyalty by 45% it should be preferred to the 48% increase obtain be 10 variables. Scientific Research Process There are four steps of the scientific research process: 1- Defining the broad problem data. The problem space can be defined as all possible situations needed for research and problem solving. It means that the specific issues that need to be investigated may not be identified at this step. For example, areas where the manager believes there is a need for important e.g. training programs do not yield results as expected.  The broad problem is should be reduced to specific problems. For this goal, preliminary data must be collected by the researcher. 2- Preliminary data collection and literature research. Part 1: Interviewing or library research helps the researcher define the problem more specifically and develop his/her theory. Certain information about economic agents can be obtained from various different searches e.g., websites, archives, and published records. Data were collected from existing sources and called as “secondary data”**** such as statistical data. Part2 Literature Research: Reasons for conducting the literature research: a) To ensure that variables that have been found have an impact on problems. b) To ensure that research subjects from previous research are not excluded. c) In preliminary research, some ethical variables may not have been identified. Therefore, the researcher must examine important research on the subject. A good literature research ensured that: a) Important variables affecting the research, or the subject being studied are not excluded from the research. b) It gives a clear idea of which variables are most important in solving the problem, they are important, and how to investigate them. c) The testability and reliability of research findings are increased. d) The problem is defined precisely and clearly. e) The risk of making an effort to rediscover/find something that already exists is avoided. f) The research conducted is appropriate and meaningful by the scientific community. Steps of literature view: Step1: Identify and access published or unpublished materials on the subject of research. Step2: Obtaining those materials. To identify resources related to the subject we can use: Bibliographic databases, Abstract databases, Full-text databases. 3- Problem definition. After preliminary data collection and literature review, the research narrows down the broad problem are to specific problems. Problem definition must be clear, complete, and concise definition of the subject that is examined. PS: A problem does not mean that something is wrong with the current situation. Correct answers indicate problems will improve the current situation.  4- Theoretical structure and development of hypotheses. Models Conceptual Models Operational Models (Empirical work) Generalization a) Statistical generalization: reach some conclusion from different statistical methods. b) External generalization: if you can extend the research of a sample to a population. Research Variables Variable: The properties of an object or event that can take different values are called variables. Ex: Age, number of employees, etc. A research examines the relationship between variables. Ex: Is there a relationship between education and financial success? school years earnings variables Literature Research Demonstration - ktp.yildiz.edu.tr - click “kampüs dışı erişim” - 2nd “tıklayınız” “Google Scholar” Start with broad and general words for research. (google scholar is not enough) E- Kaynaklar -> E- Referans Kaynakları (important resources) One of the most important resources is “web of science”/” scopus” Find a chain of citations that leads to your target research area. “Scite Ai” Uses ai for literature research. “Supporting articles” function makes the process easier. “Elicit.com” -> needs subscription Summarizes articles in this literature. Research Variables***** 1- Dependent Variable 2- Independent Variable 3- Moderator Variable 4- Mediator Variable Independent variable explains the dependent variable. 1- Dependent Variable (left hand side variable): Must be one. It is the main variable that the researcher is interested in. Researcher’s purpose is identifying and understanding the dependent variable, explaining its variability, and guessing it. Ex: A researcher might try to understand why some athletic teams are more successful than others. The dependent variable in this case is athletic achievement. Crime -> Education Earnings -> Education (dependent) (independent) (dependent) (independent) 2- Independent Variable (right hand side variable): Can be more than one. Independent variable is the variable that affects the dependent variable positively or negatively. A one unit increase or decrease in the independent variable causes a certain increase or decrease in the dependent variable. Ex: Practice Time Player Quality Athletic Team Success Teamwork (Dependent Variable) Coach Quality (Independent Variables) Ex: New Product Success Stock Price Consumer Behavior (Dependent Variable) (Independent Variables) 3- Moderating Variable: measures the slight of the relationship. It is a variable that has a strong unexpected effect on the relationship between the dependent and independent variables. The presence of a third variable (moderating variable) changes the original relationship between the dependent and independent variable.  Ex: The weight of the computer has a negative effect on the customer satisfaction: Computer Weight Customer Satisfaction (independent) (dependent) Laptop/ Desktop Ex: Diversity in the Moderator Organizational Workplace Effectiveness (independent) (dependent) Managerial Expertise 4- Mediator Variable: usually unknown/unmeasurable. Independent variables directly affect the dependent variable. The mediator variable enters causal relationship between the independent variable and the dependent variable. If there is a mediator effect (variable), the whole or partial effect of the independent variable is indirectly reflected on the independent variable. Ex: Price Computer Weight Satisfaction Ability Education Earnings **** in the exam, look at the arrows and shapes Independent Moderator Dependent Mediator Theoretical Structure It should have the following basic features: 1- Variables considered appropriate for research should be clearly identified and defined in the discussion. 2- The discussion should address how they relate to each other and how they affect each other. 3- If relationships between variables have seen noted in previous research, it should be discussed whether the direction of these relationships will be positive or negative. 4- It should be clearly stated why we expect these relationships. 5- The theoretical model can be explained graphically. (In economics, we don’t always use theoretical models with graphs.) Hypothesis Development These are statements or analyses thar are put forward regarding the problem under investigation and whose truth or falsehood has not yet been tested. Ex: Healthier employees take less sick leave. Hypothesis Types: 1- Null Hypothesis: It is a proposition that states the exact and complete relationship between two variables. It is established that there is no relationship between two variables. 2- Alternative Hypothesis: It is a proposition that states that there is a relationship between two variables or difference between two groups exists. Directional And Undirectional Hypothesis If the relationship between two variables or the difference between two groups compared and positive, negative, large, small, etc. terms are used, it is a directional hypothesis. If we don’t then it is an undirectional (non-directional) hypothesis. Ex: People who experience a lot of stress at work have less job satisfaction. (directional) There is a relationship between age and job satisfaction. (non- directional) Steps of Hypothesis Testing 1- Null (H0) and alternative (H1) hypothesis are determined. 2- The appropriate statistical test is determined. 3- The significance level is determined. 4- It is checked whether the significance level obtained as a result of the analysis is met. 5- According to the result, the null hypothesis (H0) is accepted or rejected. Earnings: β0+β1 Education+ ε If you (accept) -> H0 : β1 = 0 Then -> There is no relationship between education and earnings. If you (reject) -> H1 : β1 =/ 0 Then -> There is a relationship between education and earnings. Scientific Research Process Research Types 1- According to the purpose of the research a) Exploratory Study (research) It is applied when there is no information about the subject under investigation and when there is no information obtained from the past about how similar problems and research topics were solved. After this study, the model is developed and detailed research design is created. b) Descriptive Research Descriptive research (study) is the study conducted to describe and investigate characteristics of variables of interest. Ex: Public opinion research companies determine political opinions. Thanks to descriptive studies, researches we: Understand the characteristics of a group in each situation. Think systematically. Find new ideas for further research. c) Hypothesis Testing (used a lot in economics) It is done to explain the nature of certain relationships. The independence or dependence of two or more factors of situation is investigated. d) Case Study (not common in economics, more common in business/medicine) Case analysis is a technique of comprehensively examining one more situation similar to the problem examined by the researcher. 2- According to the Situation Under Investigation a) Casual Research There are two variables, and an attempt is made to understand which one is affected by the other. b) Correlation Research The changes of two variables together are discussed. c) Field and Laboratory Research Relational studies carried out in economic agents are called “field studies” and studies carried out to reveal cause-effect relationships using the natural environment are called “field research”. Experiments carried out to establish a cause-effect relationship by creating artificial environments in which external factors are called “laboratory research”.  3- According to Dataset a) Cross-sectional Studies The observations change not the time. Ex: In 2020, inflation rates in cities Adana…..İstanbul….. (81 cities) inflation at 2020 b) Time-series Research Time changes not the observation. Ex: 1990-2020 inflation rate in Adana 1990……..2020 (inflation) Adana city c) Panel Studies Both observation and time change. Ex: 1990-2020 in 81 cities. Adana……..İstanbul……… 1990………2020 Scale It is the quantitative evaluation of various characteristics of objects, processes, and phenomena. Types of Scale: 1- Nominal Scale (Classification Scale) A classification scale is one that allows the researcher to assign objects to specific categories and groups. PS: We can’t order. Ex: gender. 2- Ordinal Scale These are scales indicate the order of objects or alternatives within their groups. PS: We can’t order. Ex: best to worst. 3- Interval Scale These are scales that do not have absolute zero (arbitrary zero point) but the distance between measured values are certain. Ex: Celsius. 4- Ratio Scale In this scale, zero is absolute and values are equally scaled. Ex: Income. Measurement Methods 1- Two-choice scale Used to provide a yes or no answer. Ex: do you have a car? -yes -no 2- Categorical Scale Used to get a single answer from many options. Ex: which district do you live in? -kadıköy -üsküdar -esenler 3- Likert Scale***** It is a 5 or 7 point scale (rarely 3 or 9 points) Ex: 5 point example: 1 strongly disagree 2 disagree 3 undecided 4 agree 5 strongly agree In our company, project information is expertly recorded. 4- Semantic Difference Scale There are the meaning given to a certain stimulus. It is formed by pairs of adjectives that are opposite to each other. Then it is asked how appropriate the opposite adjectives are for a given word. Ex: Beautiful X Ugly Strong X Weak Economics: Reliability and Validity If we can measure the feature we are working on and express it numerically, we can evaluate and explain them scientifically. Standardized scales are called objective scales. For the scale to be standardized and subsequently have the ability to produce appropriate information, it is required to have 2 features (reliability and validity) Reliability Reliability is the consistent results that emerge with repetition, in that a measurement tool always measures what it measures in the same way. It is an indication of the stability of measurement values. Since it is impossible to have an error-free measurement increasing the reliability of measurement is possible by minimizing the error. In practice, assuming that the errors are distributed randomly, the errors develop randomly in positive or negative directions, and the average of the measurement errors becomes zero thanks to the elimination of each other.  actual value observed value error term meaning: we can never have the actual value. E (epsilon): is the difference between the measured value and actual value. In practice, we can’t have randomly distributed error-terms. PS: The calculation of the reliability coefficient is theoretical*. Since it is not possible to know the actual value in practice. For this reason, methods have been developed to indirectly calculate the reliability coefficient for different situations. ***** Important for collecting your own data Secondary data probably they did their own. Methods of Calculating Reliability Coefficient 1- Kudar- Richard Reliability Coefficient (the old way) The dataset is created by giving “x” point if the answers received from the scale have the desired feature, and “0” point if they do not have the desired feature or are left blank. 2- Cronbach’s Alpha Coefficient (the one that matters) It is an internal consistency estimation method that is appropriate to use when items are not scored as true or false, but are scored as 1-3, 1-4, or 1-5. Cronbach’s alpha coefficient is a weighted standard change that is calculated as dividing the sum of the variances of the K item in the scale to the overall variance. (0.00, 0.20) weak (0.21, 0.40) mediocre (0.41, 0.60) medium (0.61, 0.80) strong will be enough for scientific research (0.81, 1.00) excellent PS: this is what you look to achieve with your questionnaire questions Validity Validity is the degree to which a measurement tool can accurately measure the feature it aims to measure without confusing it with any other feature. It means that measurement tool measures the quality it plans to measure. In order to measure the current concepts, the meanings given by the scale and the participant must be the same. Types of validity 1- Predictive Validity It is the prove that the results obtained from a measurement tool can predict that an individual is capable of performing a certain task or will behave in a certain way. Ex: ales exam results have predictive validity if they help us accurately predict candidates’ performance in the grad school. High validity mostly depends on the ability to express the variable to be measured. Therefore, validity might be higher in direct measurements, but validity might be lower in indirect measurements because the variable is not defined sufficiently or/and the criteria are not sensitive enough. The validity coefficient takes values between -1.00 and +1.00. The higher this coefficient is, the better the scale serves the purpose. 2- Content Validity It is the prove that the content of the questions that make up a survey accurately represents the qualities intended to be measured. Ex: a survey conducted an higher education issues can be said to have content validity if it includes, to a certain extent, the facts, words, ideas, and theories used in higher education practices, directions, and instructions. 3- Construct Validity İt is the prove that a measurement tool actually measures the theoretical structure it claims to measure. Factor analysis or a comparison technique wi4h know groups can use to test it. They require a high sample size. There are two types of construct validity. A) discriminant (decomposition) validity Does each item really measure only** the characteristic we are trying to measure? B) match (numbness) validity We can determine the validity of measurement tool by comparing it with other well- known and accepted measurement tools. 4- Simultaneous (concurrent) Validity When we use different measurement methods, if we can measure the feature we aim to measure, it can be said that there is simultaneous validity between there measurement methods. 5- Face Validity If the questions appear to be valid with the concept we wish to measure without meticulous analysis (with a superficial examination), there is face validity.  *************Internal Validity and External Validity*************** External validity is the degree to which the findings can be generalized in all universes; internal validity is the degree to which the findings generalized from the sample to its population. Factors Affecting Internal Validity 1- Time (history) Effects It makes difficult to find the real cause of the change (or invariance) in the dependent variable. The probability of controlling undesirable variables decreases with time. 2- Maturation Physiological and psychological changes (maturation, fatigue, etc.) of the participants over time may be an important reason on the dependent variable. 3- Measurement Before the Experiment (testing effect) A measurement on the dependent variable is in the beginning can lead different than at the end. 4- Subject Loss During the research, some participants leave the experiment/survey due to compulsory reasons. Thus, measurements at the end will change. Factors Affecting External Validity 1- Measurement – Argument (measurement – independent variable) Interaction Groups motivated by the measurement process may also be affected differently by the independent variable. This influence is neither a quality nor a quantity that the independent variable cannot separately. Ex: while observing whether there is a change in the health habits of patients treated in hospitals, a survey administered upon admission to the hospital may motivate patients to acquire appropriate health habits and cause them to act more sensitively than patients who don’t receive such a survey. 2- Bias- Selection- Independent (Variable) Interaction In the selection of subjects participating in the research, the ability of the sample to represent the population ay not be ensured due to reasons such as not complying with the rule of impartiality or not taking a sufficient number of samples. There is a high probability that the effect of independent variable will differ from the actual situation in the population. 3- Trial Reaction As a result of the physical and psychological effects artificially created, there are some reactions that the subjects would not show their normal behaviors, these are called as trial reactions. This phenomenon, known as Howthorne Effect, is one of the most important factors that causes generalizability (external validity) problem. 4- Interaction of Independent Variables Subjects who are influenced by different variables one after another, seem unlikely to react to each new situation independently. In such a case, the order and/or application times of the independent variables may affect the dependent variable in different ways. It makes the interpretation of the result very difficult. Population Vs Sample Population All objects or individuals entering any field of observation are called the population (universe). The main population is the set of elements which the research are intended to be generalized. Working Universe It is called the universe (accessible universe) about which the researcher can express her opinion, either by observing directly or by making use of observations made on a selected sample set. Sample It was chosen from a certain population, according to certain rules. It is a small set that might be representative of the population. Three main reasons for working with a sample: 1- Cost Challenges Saving time, energy, and money. 2- Central Difficulties Small clusters are easier to control. 3- Moral Population Ethical values of the society. sample 1000 population 85 million