Flashcards in Non-Communicable Disease Deck (54)
What is analysis of variance?
ANOVA: a collection of statistical models used to analyze the differences among group means and their associated procedures (such as "variation" among and between groups), developed by statistician and evolutionary biologist Ronald Fisher.
What is attributable burden?
the burden of some disease in a certain population which is due (is attributable) to some exposure. For example, 90% of the lung cancer burden for women in Serbia is attributable to smoking, which means that if smoking was eliminated the lung cancer burden in women would be reduced by 90%
What is avoidable burden?
as the reduction in the future burden of disease if the current levels of exposure to a risk factor were reduced to those specified by the counterfactual distribution of exposure
What is an F-distribution?
a probability density function that is used especially in analysis of variance and is a function of the ratio of two independent random variables each of which has a chi-square distribution and is divided by its number of degrees of freedom
What is an F-test?
any statistical test in which the test statistic has an F-distribution under the null hypothesis. It is most often used when comparing statistical models that have been fitted to a data set, in order to identify the model that best fits the population from which the data were sampled.
What are mean squares?
estimates of variance across groups. Mean squares are used in analysis of variance and are calculated as a sum of squares divided by its appropriate degrees of freedom.
What is multiple regression?
a statistical technique that uses several explanatory variables to predict the outcome of a response variable. The goal of multiple linear regression (MLR) is to model the relationship between the explanatory and response variables.
What is a paired t-test?
a test that is used to compare two population means where you have two samples in which observations in one sample can be paired with observations in the other sample
What is primary prevention?
all interventions that attempt to prevent disease from occurring, i.e. to reduce the incidence of disease
What is the sum of squares?
a quantity that appears as part of a standard way of presenting results of such analyses. It is defined as being the sum, over all observations, of the squared differences of each observation from the overall mean
What is a Bonferroni post-hoc test?
a type of post hoc test used when you are performing many independent or dependent statistical tests at the same time
What is a Chi-squared test?
a statistical hypothesis test used to determine whether there is a significant difference between the expected frequencies and the observed frequencies in one or more categories
What is a contingency table?
a table showing the distribution of one variable in rows and another in columns, used to study the association between the two variables
What is expected frequency?
the number of occasions on which an event may be presumed to occur on average in a given number of trials
What is a Mann Whitney test?
a non-parametric test of the null hypothesis that it is equally likely that a randomly selected value from one sample will be less than or greater than a randomly selected value from a second sample.
What does non-parametric mean?
a type of test that does not make assumptions as to the form or parameters of a frequency distribution
What is observed frequency?
the actual frequency that is obtained from an experiment
What does parametric mean?
a test that assumes the value of a parameter for the purpose of analysis
What is a post-hoc test?
a test used to analyse experimental data an determine the probability of at least one Type I error in a set of comparisons
What are some examples of non-communicable diseases?
Chronic respiratory disease
How do you calculate risk difference/attributable risk?
Difference in risk between exposed and unexposed (Re - Ru)
How do you calculate the attributable fraction amongst exposed?
Percentage of cases that can be attributed to the exposure
(Re - Ru) / Re x 100%
What are the levels of prevention?
What is primordial prevention?
Prevention that targets the social (cultural) economic, and environmental determinants of health. (i.e. poverty, war, discrimination)
What is primary prevention?
Prevention of initial disease onset
Which people are targeted by primary prevention?
People with no sign of disease, asymptomatic
What is a pro and con of primary prevention targeting an entire population?
Pro: Everyone stands to benefit
Con: Difficult to motivate people to change behaviour
What is a pro and con of primary prevention targeting high risk individuals?
Pro: High potential to benefit; target people motivated
Con: Limited impact; difficult to find targets
What is secondary prevention?
Preventing further development of disease