Exam 3 Study Guide Flashcards
What is a subset of a population that is used to make inferences about the target population?
Sample
What represents an assemblage of all possible observations?
Population
What are characteristics of a population; measures of central tendency and variation?
Parameters
What are individual members of a population?
Elements
What is a subset of a population that are usually chosen in an unbiased manner (randomly) so that you can make inferences about the target population?
Sample
What are the characteristics of samples that serve as estimates of parameters?
Statistics
Mean, median, variance and standard deviation are referred to as what?
Parameters
What are used from a sample to estimate the parameters of a target population?
Statistics
Population = what? Sample = what?
Parameter
Statistics
All elements of the universe are selected for the sample the probability of being selected is 100%, this describes what?
Census
Every element in the universe has an equal probability of being selected for the sample, the probability that a specific element will be selected is independent of the selection of other elements, describes what?
Simple random Sample
The target population is first divided into relatively internally homogenous groups or strata, random samples are then drawn from each strata, guarantees representation from each group or strata describes what?
Stratified random sample
The investigator randomly selects a group or cluster, random samples are then drawn from each selected group or cluster describes what?
Cluster Sample
Elements are selected from the population in a systematic way, ex: every fifty element is selected, usually provides the equivalent of a simple random sample without using randomization
Systematic sample
What occurs when some members of the target population are less likely than others to be included in a sample resulting by definition in a non random sample or systematic deviation between characteristics of members of the sample and the population from which it was drawn?
Sample bias
The random sampling distribution of means will always tend to be normal, irrespective of the shape of the population distribution from which the samples were drawn, the mean of the random sampling distribution is equal to the mean of the original population from which the samples were drawn describes what?
Central Limit Theorem
Sum of values for all observations in the sample divided by the total number of observations describes what?
Mean
The value that falls in the middle of all observed values, 50th percentile, first order all values from least to greatest and then take middle value describes what?
Median
The most common value, sometimes there can be more than one, the value with the most observations describes what?
Mode
The proportion of the truly diseased individuals who tested positive for the disease according to the screening test is know as what?
Sensitivity
The proportion of truly non diseased individuals who tested negative for the disease of interest is known as what?
Specificity
The proportion of patients with positive tests that truly have the disease of interest describes what?
Predictive value of a positive test
The proportion of patients with a negative test that truly don’t have the disease of interest describes what?
Predictive value of a negative test
What is characterized by the amount of disease in the whole population and influences both the PV+ and the PV- tests?
Prevalence
Apply a relatively simple, inexpensive test to a large number of asymptomatic ppl in order to determine if they are likely or unlikely to have the disease that is the target of the screening program and has the desired outcome of reduced morbidity and mortality from the targeted disease among the persons screened describes what?
Screening
