Sample, sampling and sample size
In statistics population is a set of similar items or events which is of interest for some experiment. Statistical population can be a group of people, objects or even events that have a common characteristics.Collecting data on the whole population is impossible because it is too large or too geographically dispersed thats why we then choose a sub group which is called a sample. A sample is a subset of the population chosen for a survey or experiment. Sample represents the total population. If you choose a sample wisely and correctly it will be a good representation.
Sampling is a process of selecting a subset to estimate characteristics of the whole population. Sampling is
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This method includes getting participants wherever is convenient and wherever you can find them. example (stopping random people on the street and asking questions). Convenience technique is effective when conducting pilot data collection. Other advantages are simplicity, cheap to implement, easy to do, data collection can be facilitated in a short time frame. Disadvantages and main reasons why use of this sampling method is discouraged by researchers are high vulnerability to selection bias, influences that can not be controlled by the researcher, high level of sampling error. Studies that used convenience sampling also have low …show more content…
example ( selecting 4 balls form the bowl with your eyes closed). Advantages of this sampling technique is minimal sampling bias, research findings can be generalized and also large sampling frame is available. Disadvantages being that they are expensive, time consuming and difficult to organize.
Systematic random sample is a technique in which individuals are selected according to a random starting point and a fixed interval. Interval is determined by dividing the population size by the wanted sample size. This statistical method is used often because it is done faster than simple random sample, easier to execute and has low risk factor. Disadvantages may be not being able to calculate the interval because population size is not available. Data can be manipulated.
Stratified sampling is method that involves dividing the population into smaller groups known as strata. Strata are formed based on characteristics that members share. Random samples from each stratum is taken, proportional to the stratum size. Subsets of the stratum are then taken to form a random
2. There are two methods for collecting demographic data, static and dynamic. The static method of collection, also known as time specific, looks at existing populations and classifies age classes from samples of individuals living a population (inventories). This method also includes looking for evidence
1) Demographic is the statistics of the human population using variables such as age, income, education, religion ethnicity ECT.
To get my primary data I will be using a random sampling. To do this I
...ristics such as age, race, gender, education etc. The only way to use this sample is if other methods are not available. In order for a purposive sampling approach to be successful, researchers need to be careful and not use results from previous convenience samples (Purposive sampling, 2012).
Population: A population refers to a group of individuals or set of items with the desired characteristics that the researcher would like to examine, analyze and understand. It is a set of all the subjects or entities that the
As it is impossible for researchers to study an entire population, sampling theory studies a target population under study. A target population refers to a group of individuals who meet the sampling criteria for a particular study. For example, male, 20 years with type 1 diabetes. The two different types of sampling design are probability and nonprobability sampling. Probability sampling is the type of sampling plan where each person in the population has an equal opportunity to be selected for the sample, whereas in nonprobability sampling methods, not every element or person in the population has a chance to be selected for a study. This type is a more common method used in nursing research because of the limitations of the availability of
Simple random sampling is when every subject of the sample size representing the population has the same and equal opportunity of being chosen. Incorporating randomness and an equal likelihood of selection is quite difficult for a human, for he or she is naturally prone to bias (whether on purpose or without knowledge and desire). Placing names in a slip of paper and them mixing them around in a box is not as random as we believe or expect it to be. In fact, the act of such method brings its bias because it is a human controlling the selection; the mixing could possibly not be thorough enough, affecting unfairly the probability of a name being picked as opposed to another. This process could also become unreasonable, time consuming and expensive
Sampling bias (pg. 112) – a sampling method can be called biased if the results of the research found favors the outcome the researcher is looking for. The researcher ultimately controls/influences whether the results are biased and potentially misleading. If a researcher thinks that football players are more susceptible to concussions, the researcher may only look at specific positions where the players take more hits to the head for their research which could affect the results looking at football players as a whole.
One of the best things about simple random sampling is the ease of assembling the sample. It is also considered as a fair way of selecting a sample from a given population since every member is given equal opportunities of being selected. (www.explorable.com)
The Advantages and Limitations of Social Surveys in Sociological Research To survey something, is to carry out a systematic overview so that a researcher can produce a comprehensive general report on it. Survey method is often used by positivist sociologists seeking to test their hypotheses, and to investigate causes and examine variables. As with every other sociological research, survey has its own advantages and limitations. Positivist research, which is in the scientific tradition, begins with a hypothesis that can be either confirmed or rejected according to the data collected. One of the significant advantages of survey method is that, it can be used to collect data that is a representative of a larger population.
Selecting the subject otherwise, i.e. through certain groups of people or even personal friend would make the experiment unethical. I will use random selection to select my participants; more specifically I will select 100 participants, being women, from a population of over 500 women living in a battered women’s shelter. The women chosen to be in the study must range from the age 22-44. I will then put 50 in a group and the other half in another based on a color selection from a box of 50 blue cards and 50 red cards. I will be sure to have all sorts of different ages in each group to maintain validity.
However, sample data finds applications in several researches that require estimating unknown population parameters (Portney & Watkins, 2009)
A simple test to determine if a sample is representative of a population is the z-test. The z-test is heavily used to determine if the sample is representative of a population. After z has been ...
2. Determining the Sample Frame: A sample frame is a representation of the target population.
Lack of response is the main disadvantage for mail surveys. The group survey is another low cost form, however the individual respondent is interviewed in a group. The disadvantage with group surveys are the logistics of marshaling the respondents to one location and the perception by respondents that grouping posses less anonymity. Electronic surveys are a relatively new addition in survey research and could very well become comparable to the telephone survey. Electronic surveys are advantageous for the low cost as well as ease in delivery. Because the delivery method is through internet, and the general population does not