The survival data depend on the time and it render standard methods in which the survival times are frequently censored . Censored data arises when the study end and the patient still alive, a patient is lost to follow-up during the study period, and, if a patient is experience event but not the event of interest. The feature that characterizes such data is that the event not necessarily has occurred in all patients when the time of study ends. In addition, full survival time for patients can be unknown . The survival time often called a failure time or event time is a time interval between a starting point and a subsequent event
Authors Study objectives Population Involvement/theoretical model Results/Conclusions Anagnostopoulos et al., 2012 Examination of associations between illness perception, self-efficacy, perceived benefits and barriers related to mammographic screening and its predictive value. N=408 (female, age group ≥40 years, no personal history of cancer) The Common Sense Model of Self Regulation (CSM + SRM) - theoretic standard for conducting research on health beliefs, disease representations and women’s habits to undergo mammograms. The results support bivariate significant associations between health beliefs with regard to breast cancer and certain representations of the disease which correlate with multiple benefits of mammographic screening, fewer
In these clinical studies8-10,22-23, differences in failure rates and contradictory results are noteworthy. Thus, direct comparison between studies testing identical materials should be interpreted with caution, as there is no standardized protocol for clinical studies. 24 In in vivo studies, socioeconomic and dental status of patients, and malocclusion classification and resultant mechanotherapy may affect the outcomes. Furthermore, masticatory forces varying with facial type, culturally influenced dietary habits, and sex differences may also influence the results. 4 The bond failure rate of green gloo found 5.00 % at the end of 24 months.
However statistical methods are most prevalent in the field of population ecology where huge amounts of data are often analysed. The following essay will report on how statistical methods of data collection and analysis are vital in understanding the cause and extent of population
During simulation, detailed imaging scans show the location of a patient’s tumor and the normal areas around it. These scans are usually computed tomography (CT) scans, but they can also include magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasound scans. After simulation, the radiation oncologist then determines the exact area that will be treated, the total radiation dose that will be delivered to the tumor, how much dose will be allowed for the normal tissues around the tumor, and the safest angles (paths) for radiation delivery. Radiation can come from a machine outside the body which is called as external-beam radiation therapy or from radioactive material placed in the body near cancer cells which known as internal radiation therapy. Radiation therapy can cause both acute and chronic side effects.
These provide additional details about the safety and efficacy profile of the new drug. There are extensive studies on different formulations of new drug, various amount of dosages, the duration of treatment if it interacts with other drugs and safety profile. Trials can be conducted in patients with new age groups, different races, and various other types of patients.An important aspect of this phase of trials is the detection of previously unknown or inadequately quantified adverse reactions and various related risk factors. Sometimes experimental versus observational nature of experiments are distinguished from each other by use of the term post-market surveillance for the later. References: 1.
The demographic transition model helps explain the changes in the population dynamics such as growth rates and how these changes affect the population. It aids the demographers in improving the understanding of the current population growth rate. The data obtained is significant in addressing economic and social policies in the nation. Apparently, when the population changes the amount of food supply will ultimately be affected. The stages of demographic model are greatly influenced by the level of industrialization of the country.
A sample is therefore a representative part of the entire population or an extract thereof from which to generalize back to the whole population. Sampling is the process by which inference is made to the whole population by examining a part of the population (Dickersin:1990). The purpose of sampling is to provide various types of statistical information of a qualitative or quantitative nature about the whole or entire population by examining a few selected units. The sampling method is the scientific procedure of selecting those sampling units which would provide the required estimates with associated margins of uncertainity, arising from examining only a part of the population and not the whole or entire population. (Tashakkori & Teddlie 1998: 47), As mentioned above the office of the AG has a population of 95 members of staff including the top three
Such simulations also neglect unimportant and irrelevant details, leaving behind only the basic and necessary principals for a systematic study. Yet, it would still be better if the predictions of these models could be tested in biological populations. However, this would be possible only in species that evolve quickly in controlled and measurable laboratory settings. Major omissions from these simulations include learning, development and other social influences. Such considerations should be introduced into the models in the near future for better understanding of the effect of strategies on
It is also usually a quicker method than, for example, tabulation, the census technique or analysis. 3. Scope of sampling is high The aim of Sampling is to determine generalizations of data of its target market population. Using the whole population to arrive at general conclusions would be practically difficult as in very large populations the population might change before the process is completed. Some populations are also too large so that all their characteristics cannot be measured.