Research methodology basics

 To obtain evidence that his dogmatism measure is really measuring dogmatism , the investigator needs to focus on construct validation , which is the process of gathering evidence to support that a test measures the intended theoretical construct —in this case, dogmatism . 🔍 Why the Concern? The investigator is wisely questioning whether the observed correlation (r = 0.60) between dogmatism and anthrocentrism might be due to confounding factors , measurement error , or that the dogmatism scale is not valid . This skepticism is essential in construct validation . ✅ Steps to Strengthen Construct Validity of the Dogmatism Measure: 1. Content Validity Action : Involve multiple subject matter experts to review the test items to ensure they cover all relevant facets of dogmatism (e.g., rigidity of belief, resistance to change, intolerance of ambiguity). Purpose : Ensures the scale has comprehensive and representative content. 2. Convergent Validity Action : Corre...

 Here's a detailed analysis of each assertion, identifying whether it refers to reliability , validity , or both , and specifying the type of each: 1. "The test was given twice to the same group. The coefficient of correlation between the scores of the two administrations was 0.90." Refers to : Reliability Type : Test–retest reliability Explanation : This describes the consistency of the test over time. A correlation coefficient of 0.90 indicates very high temporal stability of the test scores. 2. "Four teachers studied the items of the test for their relevance to the objectives of the curriculum. The items seemed to be a good sample of the item universe." Refers to : Validity Type : Content validity Explanation : This reflects expert judgment about whether the test items adequately represent the curriculum objectives and the full domain of content (the "item universe"). 3. "Between a test of academic aptitude and gr...

 The statement: "Since the reliability of the test of logical thinking is only 0.40, its validity is negligible." contains a partial truth , but it also reflects a misinterpretation of the relationship between reliability and validity . 🔍 Key Concepts Clarified Concept Explanation Reliability The consistency or stability of test scores across time, items, or raters. Validity The degree to which a test actually measures what it claims to measure. ✅ What’s Correct in the Statement? Reliability places an upper limit on validity : A test cannot be highly valid if it is very unreliable . If reliability is very low (e.g., 0.40), the measurement is inconsistent , and it’s hard to argue that it’s accurately measuring anything—let alone logical thinking. This is based on the psychometric principle: r x y ≤ r x x ⋅ r y y r_{xy} \leq \sqrt{r_{xx} \cdot r_{yy}} r x y ​ ≤ r xx ​ ⋅ r yy ​ ​ where r x y r_{xy} r x y ​ is the validity, and r x x , r y y r_{xx}, r_...

  The statement: "My creativity test really measures creativity because I had an expert on creativity carefully screen all the items of the test." shows an oversimplified and incomplete understanding of the concept of test validity , especially construct validity and content validity .  Understanding the Claim The speaker is arguing that the test measures creativity because an expert reviewed the test items. This refers to content validity —i.e., whether the test appears to cover the domain it's supposed to measure.  What’s Reasonable in the Statement? Expert Review Supports Content Validity : Having a qualified expert review and screen test items is a valuable step in establishing content validity . The expert can ensure the items reflect recognized dimensions of creativity such as: Fluency (number of ideas), Originality (uniqueness of ideas), Flexibility (variety of ideas), and Elaboration (detai...

  The statement: "The reliability of my creativity test is 0.85. I can therefore be reasonably sure that I am measuring creativity." contains a fundamental misunderstanding of the concepts of reliability and validity in psychological testing and measurement.  Understanding the Concepts Term Definition Relevance Reliability The consistency or stability of test scores over time, forms, or raters. A test with reliability of 0.85 indicates high internal consistency or temporal stability. Validity The degree to which a test actually measures what it claims to measure. Validity is essential to conclude that a test measures "creativity" rather than something else.  What’s Correct in the Statement? A reliability coefficient of 0.85 is statistically strong . It indicates that the test produces consistent results over repeated applications or ...

 Yes, ✅ sample size determination is based on statistical principles and can be calculated using formulas , especially in quantitative research. The appropriate sample size depends on : 🔹 Factors That Determine Sample Size Factor Description Population size (N) Total number of individuals in the population Margin of error (E) Acceptable difference between sample result and population parameter (e.g., ±5%) Confidence level (Z) Degree of certainty (e.g., 95% = Z value of 1.96; 99% = Z value of 2.576) Standard deviation (σ or p) Variability in the population; estimated proportion if binary variable (e.g., 0.5 is max variability) Power of the test (1 - β) Probability of correctly rejecting a false null hypothesis (usually set at 80% or 90%) 🔹 Common Formula for Sample Size (for Large Populations) If population is large or infinite (N > 10,000), and you're estimating a proportion , the sample size is calculated as: n = Z 2 ⋅ p ⋅ ( 1 − p ) E 2 n...

    Definition: Sample design is the framework or plan used to select a subset ( sample ) of a population for observation and analysis . It determines how many , whom , and how to select participants that will represent the larger population in a research study. Effective sample design ensures that the data collected is valid, reliable, and generalizable .   Components of a Sample Design Component Description Target Population The total group the researcher wants to study (e.g., all mutual fund investors in India) Sampling Frame A list or database from which the sample will be drawn (e.g., AMFI investor list) Sampling Unit The basic unit selected for sampling (e.g., individual investor, household) Sample Size The number of units selected from the population (e.g., 400 respondents) Sampling Method The technique used to select sam...