পদ্ধতির তুলনা করুন

	গবেষণা নকশার প্রকারভেদ	গবেষণায় নমুনায়ন পদ্ধতি (Sampling Methods in Research)
ক্ষেত্র	গবেষণা পদ্ধতি	গবেষণা পদ্ধতি
পরিবার	Process / pipeline	Process / pipeline
উদ্ভবের বছর	1963	1950
প্রবর্তক	Donald T. Campbell and Julian Stanley (1963); William Shadish, Thomas Cook, & Donald Campbell (2002)	William G. Cochran and Leslie Kish (1950s–1970s)
ধরন	Framework	Framework
মৌলিক উৎস	Campbell, D. T., & Stanley, J. C. (1963). Experimental and Quasi-Experimental Designs for Research. Rand McNally.	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons.
অপর নাম	research designs, experimental and observational designs	sampling strategy, sampling design, probability and non-probability sampling
সম্পর্কিত	3	3
সারসংক্ষেপ	Research design is the overall structure and strategy of a study, encompassing decisions about how to collect, organize, and analyze data to answer research questions. Major design types include experimental (randomized controlled trials), quasi-experimental (non-random assignment), observational (no manipulation), and qualitative (exploratory, interpretive). Donald T. Campbell and Julian Stanley's 1963 seminal work established systematic terminology for internal validity threats in each design type. Modern classifications (Campbell et al., 2002; Creswell & Plano Clark, 2011) also include mixed-methods designs combining quantitative and qualitative elements.	Sampling is the process of selecting a subset of individuals, observations, or units (the sample) from a larger population to study. Sampling methods are broadly classified into probability (random) and non-probability (non-random) approaches. Probability methods—random sampling, stratified sampling, cluster sampling, systematic sampling—enable statistical inference to the population and allow calculation of confidence intervals and margins of error. Non-probability methods—convenience, purposive, snowball, quota sampling—are practical for exploratory or qualitative research but do not support formal statistical generalization. Cochran's Sampling Techniques (1977) and Kish's Survey Sampling (1965) are foundational references; modern applications span surveys, experiments, qualitative studies, and clinical trials.