Descriptive statistics(2) Qualitative data
Descriptive statistics (2) Qualitative data 1
Another classification numerical variable categorical variable binary variable/ dichotomous polytomous variable multinomial Ordinal(or ranked data
2 Another Classification numerical variable categorical variable binary variable/ dichotomous polytomous variable multinomial Ordinal (or ranked data)
Descriptive statistics for categorical data Relative number and application tabular and graphic methods
3 Descriptive statistics for categorical data • Relative number and application • tabular and graphic methods
numerical method -Relative number Rate Proportion Ratio
4 numerical method -Relative number • Rate • Proportion • Ratio
Rate In contrast to the static nature of proportions rates are aimed at measuring the occurrences of events during or after a certain time period (1)Changes (2) Measures of morbidity and mortality
Rate • In contrast to the static nature of proportions, rates are aimed at measuring the occurrences of events during or after a certain time period. • (1) Changes • (2) Measures of Morbidity and Mortality 5
Change rate 10o 88 Relapses of 10 Korean veterans Returning Vietnam veterans Immigration 8品 1940 1950 196o 197o 198o 1990 YEar Figure 1.6 Malaria rates in the United States, 1940-1989. new value- old value change rate(%)=—old value 产×100
Change rate 6
Rate-Force Index a+b A single figure that measures the forces of specific events, for example death, disease. mortality morbidity) a= the frequency with which an event has occurred during some specified period of time a+b= the number of person exposed to the risk of the event during the same period of time K=some number such as 100, 1000, 100,000
7 Rate-Force Index • A single figure that measures the forces of specific events, for example death, disease. mortality & morbidity) • a= the frequency with which an event has occurred during some specified period of time. • a+b= the number of person exposed to the risk of the event during the same period of time • K=some number such as 100,1000,100,000 a k a b +
Vital statistics-Rates as measure of health status Incidence rate(morbidity n newcases during lyear total population on July1 prevalence rate n cases at l po int in time total population at that point in time
8 Vital Statistics-Rates as measure of health status. • Incidence rate (morbidity) • prevalence rate 1 1 n newcases during year total population on July 1 int int n cases at po in time total population at that po in time
Measures of morbidity and mortality Unlike change rates these measures are proportions 3 types of rate are commonly mentioned crude, specific, adjusted (or standardized) Crude rates are computed for an entire large group or population; they disregard factors such as age gender and race Adjusted or standardized rates are used to make valid summary comparisons between 2 or more groups possessing different age distributions
Measures of Morbidity and Mortality 3 types of rate are commonly mentioned: crude, specific, & adjusted (or standardized) Unlike change rates, these measures are proportions. Crude rates are computed for an entire large group or population; they disregard factors such as age, gender, and race. Adjusted or standardized rates are used to make valid summary comparisons between 2 or more groups possessing different age distributions. 9
The annual crude death rate is defined as the number of deaths in a calendar year divided by the population on July 1 of that year the 1980 population of california was 23,000,000(as estimated by july 1)and there were 190, 237 deaths during 1980 190.247 crude death rate 1000 23,00000 =8.3 deaths per 1000 persons per year Age-specific death rate
• The annual crude death rate is defined as the number of deaths in a calendar year divided by the population on July 1 of that year . the 1980 population of California was 23,000,000(as estimated by July 1) and there were 190,237 deaths during 1980. 10 •Age-specific death rate
