chapter 7 the logic of sampling. observation and sampling polls and other forms of social research...
TRANSCRIPT
![Page 1: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/1.jpg)
Chapter 7
The Logic Of Sampling
![Page 2: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/2.jpg)
![Page 3: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/3.jpg)
![Page 4: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/4.jpg)
Observation and Sampling• Polls and other forms of social research
rest on observations. • The task of researchers is to select the
key aspects to observe (sample).• Generalizing from a sample to a larger
population is called probability sampling and involves random selection.
![Page 5: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/5.jpg)
Types of Sampling• Purposive or judgmental sampling
• Selecting a sample based on knowledge of a population, its elements, and the purpose of the study.
• Used when field researchers are interested in studying cases that don’t fit into regular patterns.
![Page 6: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/6.jpg)
Types of Sampling• Snowball sampling
• Appropriate when members of a population are difficult to locate.
• Researcher collects data on members of the target population she can locate, then asks them to help locate other members of that population.
![Page 7: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/7.jpg)
Probability Sampling• Precise statistical descriptions of large
populations.• A sample of individuals from a population
must contain the same variations that exist in the population.• Representativeness: Quality of a sample having
the same distribution of characteristics as the population from which it was selected
![Page 8: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/8.jpg)
![Page 9: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/9.jpg)
EPSEM • Equal probability of selection method. • A sample design in which each member
of a population has the same chance of being selected into the sample.• Is that possible?
• Telephone• Face-to-face
![Page 10: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/10.jpg)
Parameter• Summary description of a given variable
in a population.
![Page 11: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/11.jpg)
![Page 12: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/12.jpg)
![Page 13: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/13.jpg)
![Page 14: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/14.jpg)
![Page 15: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/15.jpg)
![Page 16: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/16.jpg)
![Page 17: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/17.jpg)
Sampling Error• The degree of error to be expected of a
given sample design.
![Page 18: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/18.jpg)
Confidence Level• The estimated probability that a population
parameter lies within a given confidence interval.
• Thus, we might be 95% confident that between 35 and 45% of all voters favor Candidate A.
• Confidence interval - The range of values within which a population parameter is estimated to lie.
![Page 19: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/19.jpg)
Simple Random Sampling• Feasible only with the simplest sampling
frame.• Not the most accurate method available.
![Page 20: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/20.jpg)
Systematic Sampling• Slightly more accurate than simple
random sampling. • Arrangement of elements in the list can
result in a biased sample.
![Page 21: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/21.jpg)
Stratified Sampling• Rather than selecting sample for
population at large, researcher draws from homogenous subsets of the population.
• Results in a greater degree of representativeness by decreasing the probable sampling error.
![Page 22: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/22.jpg)
![Page 23: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/23.jpg)
![Page 24: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/24.jpg)
Cluster Sampling• A multistage sampling in which natural
groups are sampled initially with the members of each selected group being subsampled afterward.
![Page 25: Chapter 7 The Logic Of Sampling. Observation and Sampling Polls and other forms of social research rest on observations. The task of researchers is](https://reader035.vdocument.in/reader035/viewer/2022062422/56649f005503460f94c1615d/html5/thumbnails/25.jpg)
Weighting• Giving some cases more weight than others.• Assigning different weights to cases that were
selected into a sample with different probabilities of selection.
• In the simplest scenario, each case is given a weight equal to the inverse of its probability o selection.
• When all cases have the same chance of selection, no weighting is necessary.