Sometimes a population consists of a number of subsets (strata) such that members within any particular strata are alike while difference between strata are more than simply random variations. In such a case, the population can be split up into strata. Then a stratified random sample consists of simple random samples, with the same sampling proportion, taken within each stratum.
In a cluster sample, researchers divide subjects into strata (like cities, for example), randomly select a few strata (draw the names of a few cities from a hat) and sample every subject in those strata (question everyone in that city.) A significant disadvantage is that you may select strata that completely overlook a feature relevant to your study.
Basically in a stratified sampling procedure, the population is first partitioned into disjoint classes (the strata) which together are exhaustive. Thus each population element should be within one and only one stratum. Then a simple random sample is taken from each stratum, the sampling effort may either be a proportional allocation (each simple random sample would contain an amount of variates from a stratum which is proportional to the size of that stratum) or according to optimal allocation, where the target is to have a final sample with the minimum variabilty possible. The main difference between stratified and cluster sampling is that in stratified sampling all the strata need to be sampled. In cluster sampling one proceeds by first selecting a number of clusters at random and then sampling each cluster or conduct a census of each cluster. But usually not all clusters would be included.
Homogeneous refers to groups composed of parts or elements that are all of the same kind or nature. In stratified sampling, a population which is composed of diverse groupings is subdivided into two or more groups so that the diversity is decreased in the subgroups. For example, if the total population is composed of males and females, then stratification into subgroups of male and female will result in strata that are of the same kind with respect to the classification variable gender: i.e, the strata are homogeneous. Other classification variables or combinations of classification variables may be used to improve homogeneity.
They have used Stratified Sample. Design because stratified sample is a sampling technique in which the researcher divided the entire target population into different subgroups, or strata, and then randomly selects the final subjects proportionally from the different strata. This type of sampling is used when the researcher wants to highlight specific subgroups within the population. So in this Research this technique is used by the researcher.
a break in a sedimentary sequence that does not involves a difference of inclination between the strata on each side of the break
Sometimes a population consists of a number of subsets (strata) such that members within any particular strata are alike while difference between strata are more than simply random variations. In such a case, the population can be split up into strata. Then a stratified random sample consists of simple random samples, with the same sampling proportion, taken within each stratum.
Strata refers to distinct layers or divisions within a rock formation or other material. Stratification refers to the process of arranging or forming these layers. In essence, strata are the actual layers, while stratification is the process of layering.
Strata - Strata album - was created on 2004-07-27.
Strata management services are the professional services provided by strata managers to the owners corporations of strata schemes. The services provided by strata managers include the administration and management of the common property, the preparation and circulation of meeting agendas and minutes, the collection and payment of strata levies, the coordination of maintenance and repairs, and the provision of advice to owners corporations on a range of strata-related matters.
disconformity
When layers of rocks are deposited in a continuous succession through time without any significant break in deposition they are conformable. But if deposition is interrupted or there is an episode of erosion between deposition then the boundary between the older and younger rocks is unconformable, in essence part of the geologic record is missing.
Yes they are. Laccoliths can lift the sedementary strata they penetrate. Laccoliths are igneous rock forcibly injected between sedimentary strata.
anticline is a convex up fold with the oldest bed at the core, whereas antiform is the descriptive term used for any convex up fold. antiform should be used when the age relationship between the strata are unknown.
Strata.
A bedding plane is the area of separation between rock strata made by a cyclical or situational deposition of sediment. Bedding planes are originally parallel to the horizon, but the strata inclination can be altered by crust moving events.
The plural for stratum is strata.