SYG 4300-02Social Research MethodsFinal Review Guide: This is a broad list of concepts relevant to the final exam. I encourage you to know concepts, examples, calculations and interpretations. Sample Elements• The individual units, often individual persons, that comprise a sampleSampling Frame• List of all the sampling units from which the sample is drawnSampling Error• Sampling error is the deviation of the selected sample from the true characteristics, traits, behaviors, qualities or figures of the entire population.• Sampling process error occurs because researchers draw different subjects from the same population but still, the subjects have individual differences.• Ways to eliminate:o This solution is to eliminate the concept of sample, and to test the entire population.Representativeness• Subset of a statistical population that accurately reflects the members of the entire population• Unbiased indication of what population is likeProbability vs. Non-probability Sampling Methods• Non-probability sampling o Probability of being chosen is unknowno To satisfy concerns about the sample’s representativeness, the researcher must explicitly explain how the sample represents the population from which it was drawn. o Cheaper but unable to generalizeo Potential for biaso Convenience Sample (ease of access): sample is selected from elements of a population that are easily accessible• Probability samplingo Methods for drawing a sample in which the probability of selecting population elements is known. The researcher uses random sampling so that the representativeness of the sample characteristics to the (known) population characteristics can be statistically calculated. o Random Sample: each subject has a known probability of being selectedo Allows application of statistical sampling theory to result to: Generalize Test hypothesis Ensure representativeness and precisionSystematic Random Sample• From the sample frame, a starting point is chosen at random, and thereafter at regular intervals.• For example, suppose you want to sample 8 houses from a street of 120 houseso 120/8= 15, so every 15th house is chosen after a random starting point between 1 and 15. o If the random starting point is 11, then the houses selected are 11, 26, 41, 56, 71, 86, 101, and 116. • Advantages:o Spreads the sample more evenly over the populationo Easier to conduct than a simple random sample• Disadvantages: o The system may interact with some hidden pattern in the population, e.g. every third house along the street might always be the middle one of a terrace of three. Stratified Random Sample• A probability sample that is organized to capture known group differences among the population.• In the first stage, elements are sorted into separate groups (called “strata”) according to the selected group characteristics.• In the second stage, elements are randomly sampled from within strata. • For example, you want to find out whether workers who did a lot of overtime work had higher performance scores. If you had existing data suggesting that workers who had children were less likely to work overtime than those who did not have children, you would divide the employee population into two groups: parents and non-parents. You would then randomly select an equal number of people from each subgroup.• Advantages:o Captures key population characteristics in the sampleo Works well for populations with a variety of attributesCluster Sample• A random sampling plan in which the population is subdivided into groups called clusters so that there is small variability within clusters and large variability between clusters.• Then the required information is collected from a simple random sample of the elements within each selected group.• Advantages:o Cheaper• Disadvantages:o Higher sampling errorAvailability Sample (Convenience sample) • A nonprobability sample in which elements are drawn based on their availability to the researcher. Quota Sample• Quota sampling is a non-probability sampling technique wherein the assembled sample has the same proportions of individuals as the entire population with respect to known characteristics, traits or focused phenomenon.o The first step in non-probability quota sampling is to divide the population into exclusive subgroups.o Then, the researcher must identify the proportions of these subgroups in the population; this same proportion will be applied in the sampling process.o Finally, the researcher selects subjects from the various subgroups while taking into consideration the proportions noted in the previous step.o The final step ensures that the sample is representative of the entire population. It also allows the researcher to study traits and characteristics that are noted for each subgroup.• In a study wherein the researcher likes to compare the academic performance of the different high school class levels, its relationship with gender and socioeconomic status, the researcher first identifies the subgroups.• Usually, the subgroups are the characteristics or variables of the study. The researcher divides the entire population into class levels, intersected with gender and socioeconomic status. Then, he takes note of the proportions of these subgroups in the entire population and then samples each subgroup accordingly.• Advantages:o Allows the researcher to sample a subgroup of great interest to the studyo Allows researcher to observe relationships between subgroups • Disadvantageso May not always be representative of the populationo Traits may be overrepresentedPurposive sample• A nonprobability sample in which the researcher selects elements for a specific purpose, usually because of the unique characteristics of the elementsSnowball sample• A nonprobability sample in which the researcher asks the initial elements, usually people, to refer to other potential elements for inclusion in the sample. • The process is repeated until the sample grows (i.e., ‘ snowballs’) to the size desired by the researcherNormal Curve• A symmetrical curve representing the normal distribution Advantages of Survey Research• Versatility• Efficiency• GeneralizabilityConsiderations when designing survey questions• Avoid jargon, slang, and abbreviations• Avoid ambiguity, confusion, and vaguenesso Use of indefinite words or response categorieso First think seriously about what you want to measure and then consider the