the time sequence if exposure ad disease is usually not known
cross-sectional
R is the electrical resistance,A is the cross-sectional area,l is the length of the piece of material.
Secondary data may not answer fully answer the research questions of a study. It is also hard to establish its validity, and if proper sampling and data collection methods were employed.
Purposive sampling involves selecting participants for a study based on some characteristic that you know they have. There is nothing random about their selection - it was done with intent. An advantage of this type of sampling is that it allows the researcher to quickly hone in on the target population. A disadvantage to this form of sampling is that researcher bias can creep in to influence results, if subjects are not chosen very carefully.
A lack of flexibility and limited menu information is another disadvantage that may have surprising implications.
advantage of cross sectional study?
Yes, We can design a cross sectional study which its data collected in a retrospective format, so this study is called cross sectional retrospective study.
One disadvantage of a cross-sectional study is that it only provides a snapshot of data at a single point in time, which may not capture changes or trends over time. This limits the ability to establish cause-and-effect relationships or assess how variables may be related in a dynamic way. Additionally, cross-sectional studies are susceptible to issues such as recall bias and may not account for the influence of confounding variables.
cross sectional
Basically it is not. However, there are studies being tiltled as prospective cross sectional study, but these kind fo terms should be used with caution and clear explanation.
The advantage of cross sectional studies is that they are simple, quick, and very affordable to conduct. As a disadvantage, the results of cross sectional studies may be difficult to assess where different participants are used at different levels of an investigation.
The advantage of cross sectional studies is that they are simple, quick, and very affordable to conduct. As a disadvantage, the results of cross sectional studies may be difficult to assess where different participants are used at different levels of an investigation.
A longitudinal study is an alternative to a cross-sectional study. In a longitudinal study, data is collected from the same subjects over a period of time, allowing researchers to observe changes within individuals. This type of study provides a more in-depth understanding of how variables evolve over time compared to cross-sectional studies.
the cross-sectional study selects a sample that has all the age ranges the researchers are interested in verses one group that is followed throught time
Yes, cross-sectional studies can be classified as comparative or associative. Comparative cross-sectional studies involve comparing different groups at one point in time, while associative cross-sectional studies examine the relationship between variables within a single group at one point in time.
They can do.
cross-sectional