Video Post: Numerators & Denominators | Math Solutions
The numerators always on top. A little dirty joke to remember it. Relationships between Fractions, Decimals, Ratios and Percentages. UTAS Home the numerator is three (3) and the denominator is five (5). The numerator . The difference between denominator and numerator in a research study is the same The relationship of numerator to denominator in research depends on the.
One of these ten equal parts, or one tenth of the gridis shaded in red.
Numerators, denominators and populations at risk
One tenth, the red portion, can be divided into ten equal parts the yellow section shows this. The yellow portion is a one hundredth as of these make the whole. A one hundredththe yellow portion, can also be divided into ten equal parts the blue section shows this. The blue portion is represents one thousandths of the whole, as of these thousands makes the whole. The following statements can be made: The red area is one tenth or zero point one 0.
A visual model for decimal fractions The following video uses a thousandths grid in a similar way, to demonstrate writing decimal fractions: It is written as or 0.
It is easy to see that this shaded area is one half of the whole grid.
Numerators in fractions explained for primary-school parents | Numerators definition | TheSchoolRun
This shaded area can also be broken up into 50 hundredths. The fraction 50 hundredths is equivalent to thousandths. Furthermore, the shaded area in the video can be broken up into five tenths. The fraction five tenths is equivalent to the fraction 50 hundredths and thousandths All of these fractions have the same value of one halfand so they are equivalent fractions.
Unlike whole numbers, a zero on the end right hand side does not change the value of the decimal. Again it is useful for public health purposes if we can estimate the excess disease in a population that is due to a particular risk factor.
Measures of population impact: Estimate how much of the disease in the population is caused by the risk factor Estimate the expected impact on a population of removing or changing the distribution of risk factors in that population Compare the population and unexposed while measures of effect compare the exposed and unexposed Assume that the association between disease and the risk factor are causal There are two main measures of population impact: The population attributable risk PAR estimates the excess rate of disease in the total study population that is attributable to the exposure.
It provides a measure of the public health impact of the exposure in population, again assuming that the association is causal. The PAR is the absolute difference between the risk or rate in the whole population and the risk or rate in the unexposed group, as follows: Issues in the calculation of measures of impact: The calculation of PAF assumes that all of the association between the risk factor and disease is causal.
PAR varies according to how common an exposure to the risk factor is in the population. Standardisation A principal role of epidemiology is to compare the incidence of disease or mortality between two or more populations.
However, the comparison of crude mortality or morbidity rates is often misleading because the populations being compared may differ significantly with respect to certain underlying characteristics, such as age or sex, which can affect the overall rate of morbidity or mortality.
Definition of Numerator and Denominator
An older population will have a higher overall mortality rate when compared to a younger population. As a result, variations in age complicate any comparison between two or more populations that have different age structures.
To understand how a comparison of crude rates can be affected by differing population distributions, it should be recognised that a crude overall rate is simply a weighted average of the individual category specific rates, with the weights being the proportion of the population in each category. Presentation of category specific rates One method of overcoming the effects of confounding variables such as age is to simply present and compare the age-specific rates. While this stratification allows for a more comprehensive comparison of mortality or morbidity rates between two or more populations, as the number of stratum-specific rates being compared increases, the volume of data being examined may become unmanageable.
This is achieved by using the methods of standardisation. Methods of Standardisation There are two methods of standardisation commonly used in epidemiological studies.
They are characterised by whether the standard used is either: